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THESIS FOR DEGREE OF M. &.,
DEWEY ALSDORF SEELEY
1917

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THE CLIMATE

OF

MICHIGAN AND ITS RELATION TO AGRICULTURE.

Thesis for Degree of M. S.

Dewey Alsdorf Seeley,

19 17
THESIS
OUTLINE,

Page
INTRODUCTION
Climate and agriculture vitally related........... 1
Purpose of paper.......... wee ee eee eee cere ete ewes 1
PART I. CLIMATES IN GENERAL,
Factors controlling climate........c ccc ccc cee eces ~ i
1. Latitude... ..ccccvees wee eee e ewe eee et wees 2 2
2, Altitude... ccc ccc ccc ee ee wee e te eee tee esee 2
3S. MNVironment.,ccccccccvccscvesccsvcescsceves coe 2
4, Proximity to normal storm path....... eocccee 4
PART II. The CLIMATE OF MICHIGAN.
(a)Temperature as influenced by -
lL. Latitude... ccc ccc cw ccc wcrc ccc cw ncn ce tecee oe F
Qe. Altituder.cccccccccccccssscccvvesscccscsces » 6
3. Environment, ( Great Takes). acc ccc cr ccc ccces 7

4. Proximity to normal storm path.......cc-ccece tt

(> )Precipitation as influenced by-

1, Tatitude...ccccccccsccsesccs cece cee eee ccc ee ~ dil
De Altitude... iti 12
3S. Environment... ccccccc cess svcve cscs scccces .. 22
4, Proximity to normal storm path.......ccceee 13

(c)Cloudiness as influenced by- :
lL. Latitude... . ccc ccc ccc cece crv cc cree cnsscscscvee Id
2. Altutuderccwcwscccccccvsvcsccsccesescescsee Uh
S. Environment. .c.cccccscccsesevecscveseseccscsees I
4. Proximity to normal storm path...........06-15
(d)Wind velocity and direction as inf luenced by-
d, Jatitude...c.c cc ccc veccccscccscevccces oooee SF
2. Altitude. ccrccrecccccccersesssesecsccsecscee 16
Se FEnvironMenteccsssssscevccsvccvcscsesscvevseces IG
4, Proximity to normal storm path............6. 17
(e) Humidity as influenced by-
dL, Tatituder. ccc ccc cece ence ev cccccceccesccces o. 1a
2. Altitude... cccsececcecsee Coc e cence eaces coee IB
3S. Environment... ccccscccccccscsescvesccccsees WB
4. Proximity to norme.1 storm PAtTN.cccccccvccee . 19
(f) Other meteorological, i.e, Frost, hail, tornadoes, etc.
as influenced by-
1, Latitude... ... cece scene ccc coe ccesececccsees WD
f 2. Altitude...cccsccccccccccccee cece ee ceeeseee I
Sco UnvironmMent..cccccvcvcvcessescsercsvscsecssee IY
4. Proximity to normal storm path......cccceee IY

PART III. RELATION OF CLIMATE OF MICHIGAN TO AGRICULTURE,
(a) Crop requirements, and how well met as to-

1, Temperature. .c.cccccccccccsccccsesesesssees 22

ae COPN. ccccccvccevccccccccccecessevecs 25.

bd. Crete sees at tates tees tenes eeeeaes 26

C. r cereal CropB.....cccscccececes ars

a. Special CTOs... ee see - 108%

e. Fruit....cccece eeeee eoeoeereeoeoteteenveenvreese 25
OUTLINE (Continued. )
Qe Precipitation. ... cc cncvccnvsvenecveesecvecseces a7
a. Corre lation between rainfall and yields. 29
Oe CloudinesB. .cccccccncscccccccccscscccececceeees 29
a. Effect of in protecting fruit ,in.winter. 29
bd. Effect of in protecting wreat and rve -
in WinteY cc cccccvsccevescccccececscececee 29
c. Effect of cbundent sunshine in summer... 30
4. Wind velocity and direction. ccccccccccsvveee 20
5. HUMIAACY. ccc ccccccccsccnncsvcccccccersccccece 30

(bo). Climate not Changing... .cccccessvescececsesvevssese dU

SUMMARY. .. ccc ccc cece

@e4«e«47oe?ee8 @ oes 6eeeee5sx#eee#8 @8 @#@ @ 8@mUMOHhUhOUCOUlUMOMDUMOMUMOHUOU® 31
—_—

THE CLIMATE OF MICHIGAN AND ITS RELATION TO AGRICULTURE

Dewey A., See ley.

INTRODUCTION,

The whole realm of human activities and pursuits
is affected by weather conditions, but none more vitally
than Agriculture. The average of the weather conditions
makes up climate, and an accurate description of the
climate of any section can be used as a guide in determine
ing the suitability of any section for particular crops,
provided soil conditions are right for those crops.

It is the purpose of this paper to describe the
climate of the state of Michigan and state its suitap{fl-
ity. to variaus crops. It willbe necessary to enquire
into the factors that determine climate, at the outset,
in order to understand the peculiarities that will be

noted in the climatic conditions in different sections

PART I
FACTORS CONTROLLING CLIMATE

latitude, altitude, environment/d surroundings, and

of this state.

the location of a place relative to the path of storms,
each has. a decided influence on climate. Without
going into detail with regard to each of these it will
be sufficient to notice that the distance north or south
of the equator, other things being equal, determines

the temperature of a locadity because the sun's rays
strike the earth at a greater and greater angle with
increasing latitude. In roum nunbers the average
annual temperature decreases about one degree with each

100 miles north or south of the equator.
Altitude, or height above sea level, has an effect
on temperature analogous to that of latitude. On the
average the temperature decreases about one degree
Fahrenheit with each rise of 300 feet in height. As
a result the sumbits of high mountains are continually
snow-capped throughout the year, even in the tropics.
On the other hand slight elevations of ground which
provide good air drainage are not subject to the
extremes of low temperature or killing frosts to the
extent that low, undrained areas are, because the
cold air, being heavier than warmer air, drains off
from the hill sides into the swales. low ground is
sometimes colder by eight or ten degrees than higher
ground near by.

Elevated sections usually receive more rainfall
than lower areas, especially on the slope from which
the prevailing winds blow, because the currents of air
which are forced to rise up the slope, expand and cool
as they rise, thewby producing greater condensation and
precipitation. It will be noted Jater thah the effect
of elevation on rainfall is noticeable even in Michigan
where the differences in height above sea level are
comparatively slight.

The third factor in the control of climate,
that of environmental conditions _, is one which
is particularly important in Michigan. The effect
of the Great Lakes is marked, especially along Iakes

Michigan ard Superior, causing wide departures in

temperature and other climatic conditions, between
those sections and other regions of the same latitude

| and altitude. Lurge bodies of water heat much more
slowly in summer and cool correspondingly slowly in
winter, than adjoining land areas, so that the Great
Iukes are cool in summer ard warm in winter, compared
with the temperature of interior land areas. Tis

is due to the fact that from five to seven times the
amount of heat necessary to raise: the temperature of
a given weight of soil one degree is required to

warm the same weight of water an equal amount.

The fact that considerable heat from the sun's rays

is used up in evaporating some of the surface water
also retards rapid heating. The fact that the water
is usually in motion and any heating at the surface

is transferred to other regions, whereas in the case
of the soil this mixing does not take place am the
surface becomes superheated, is another reason why

the gaud is warmer than water areas in summer,
Furthermore insolation is transmitted and conducted
through water much more readily than through soil,
which is an additional cause of super-heating of the surface of
ljatter compared to the former, As a result of these
various factors actual tests of temperature of the water
in the @reat yakes in mid-summer show reaiings as much
ap 30°F, to 40°F. lower than soil temperatures taken
near the surface of the ground in the interior of the
state at the sane time. The prevailing westerly winds

blowing across these wide expanses of comparatively cool
water in 6 umme f.re greatly ruduced in temperature and
reach the Michigan shore as cool, refreshing breezes.

The great volume of heat that is stored up in
the lakes during the summer is held well into the winter
season. In fact only in the very coldest winters does
the water freeze solidly across , and then only for short
periods. “herefore the extremely cold northwest winds
which usher in typical cold waves in winter, are decidedly
tempered tn crossing the comparative ly warm water and
strike the eastern and southern coasts greatly increased
in temperature.
the

The fourth factor influencing cl#mate is, location
of the region relative to the normal storm path. Storms
are areas of low atmospheric pressure which travel
across the continents and ocaans in a general west to
east direction, sometimes retaining their identity
entirely around the world. On account of the fact that
the winds blow spttally inward toward the center of these
gteat low pressure areas, es they progress eastward, they
are called "Cyclones". They are great atmospheric whirls
usually covering sveral states in extent, and travel
easterly 8rom 200 to 2000 miles per day. The paths or
routes that these disturbances travel are quite well
defined. The majority of them move somewhat southeast-
ward over the western half of the country, changing their
course to northeastward when the/ weach a point a few

hundred miles this side of the Rocky Mountains. The

further south a storm goes the more pronounced is the

turn to the northward in the middle-western states.
5
As a result the majority of storms pass the region of
the Great yakes and drift eastward out the St. Lawrence
valley. These storm areas bring with them the
typical change to warmer ami unsettled weather, with
rain or snow,according to the season.

Following these disturbances areas of high pressure
or anti-cyclones usually arrive, bringing with them just
the opposite sort of weather. Most of these formations
first appear on the weather map in the far Northwest
—— whence they move southeastward, many of them towazd
the Great Lakes. As the air flows out away from these
aréas, as cold, icy blasts in winter, the wind is north-
west in advance of one of theee anti-cyc lones, somé4mes
rea&hing the required severity to be termed a "Cold wave",
Now Michigan is in the direct path of the majority of
both the cyclones and anti-cyclones, and the weather
therefore swings back and forth from one type to the
other in irregular intervals of three to five days.
Rainfall is more or less evenly distributed throughout
the year monotonous periods of extreme conditions of
any kind are infrequent and short in duration. On
the other ham regions remote from these storm pathez
are not so evenly watered and do not experience the
f luctuat ian conditions of this section.

PARTII. THE CLIMATE OF MICHIGAN,
Having outlined the factors which control climate
in general the peculiarities of the climate of Michigan

willbe more easily accounted for. The various elements

which make up climate, i.e. temperature, precipitation,
cloudiness, wind and humidity, wittl be taken up separatel y

as they are found in this state and described in order.
Michigan lies almost entirely between latitudes

42° and 47° N. tatdtude, and is therefore ahout the

same distance north of the equator as France, Switzerland,

northern Italy,..Austris and the Balkan States. Its climate

is somewhat colder that the first three countries named

but about the same in temperature as Austria and the

northern portion of the Balkans. The ocean currents

tend to cause milder weather in the three former.

The average annual temperature ranges from about 39°F

in the coldest portions of the upper peninsula to

49°F. in the southern tier of counties. Chart II

shows the isothermal lines for the year, and they

indicate clearly the decrease in temperature with

increase in latitude. The effect of altitude can be

noticed by studying the elevations shown in Chart I

in connection with the annual temperatures. The follow-

ing will serve to illustrate this effect:

Station. Elevation, feet. Mean annual temp-
erature,degrees fF,
Humboldt, Marquette Co. 1536 36.9
Newberry, Luce Co, 773 39.3
Difference 763 2.4
Ann Arbor ,Washtenaw,Co. 930 47,1
Eloise, Wayne, Co. 640 48.1
Difference 290 1,0
Hillsdale , Hillsdale Co. 1150 47,1
Adrian, Lenawee Co. 770 48.5
Difference 380 1,4

Bach pair of stations was selected to show the true

effect of elevation alone, other influences such as
 

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7
latitude, distance from lake etc. being about the same
for both stations in each pair.

The effect of the lakes on the mean annual temperatur e
is evident, yet not as pronounced as it is in the case of
either summer or winter temperatures. Chart II shows
that the temperature is lower in the interior of the state
than it is along the lake shoees, but this is probably
due more to the influence of elevation tha Jake effect.
The cooling effect of the Jakes in summer nearly balances
the warming influence in winter, Jeaving the results for
the year about the same as in the interior, at the sane
altitude.

Charts III and IV, showing the mean temperature
of Michigan for ganuary ami July, respectively, show
the lake effect more clearly. In the former the lines
bend sharply northward along lake Michigan, as the
temperature is higher on the lake shore. In the Lake
Superior region the isotherms parallel the sore line,
the temperature of the coast cities being four to six
degrees warmer than interior points but a few miles
distant. Just the opposite conditions are shown on the
chart for July. Here the lines bend sharply downward
along the Lake Michigan shore, the temperature being as
low at South pwaven, for example, as at West Branch, an
interior station more than 100 miles father north.

The most striking illustration of the lake effect
is brought out by Charts V and VI. These charts are drawn

from data recorded during the very cold month of January ,

1912, and the very hot month of July,1916, the temperatures
 

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8
used being, respectively, the Howest in Jsxnuary and the
highest in July. § The moderating effect of all the
jlakes is shown by Chart V. In the upper peninsula
realings as low as -45°F ani -46°F were registered
in the interior counties, while at “agle Harbor the
north-most station, on the Keweenaw peninsula, the
lowest reached was -17°F, In the lower peninsula
-39°F. was recorded at Gaylord, Otsego Co., but
the lowest at Old Mission, on Gram Traverse Bay,
at the same latitude, was -7°F,

The July mximum temperature chart,(Chart VI),
brings out the cooling effect of the Lakes, especially
jake Michigan during extreme ly hot weather. Here
the isotherms are crowded close together, parallel to
the shore line, indicating a rapid rise as one leaves
the lake. The highest temperature recorded during
this month of almost unprecedented heat, ranged from
93 to 96°F. on the lake shore, to as high as 105 ani
lO6f.in the interior of the lower peninsula. The
hot southwest winds in traversing I~ke Michigan were
cooled 10° or more. On the Lake Superior shore ,
however, temperatures were pructicutix as high or
even higher, than fmrther inland, because the winds
were southwesterly ami the kkke effect was not felt,
while inland the greater elevation of the land tended
to reduce the temperature somewhat.

To further illustrate the effect of the Great yakes

on temperature five tables are reproduced, herewith, as

follows: The mean mont ly temperature, mean monthly
 
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maximum temperature, mean mbéntity minimum temperature,
absolute maximum ami absolute minim, temperatures as
Gram Haven, Michigan, Milwaukee, Wis., and the average
of such temperatures at five cities in South Dakota,
Wisconsin and Iowa, having the sam latitude, as

comp lied vy Eshleman } ° The difference in temperature
between that at Grand raven and the average of the five
interior stations is noted by means of "+" ami "=" gigns.
It will be noted from Tab le I that the mean temperature
for the year is practically the sam for all stations,
but that Gran Haven is warmer in winter and colder in
summer by several degrees than the western stations, and
slightly warmer in winter and cooler in summer than
Milwaukee, because it is on the windward side of the
lake. Table II gives the average maximum temper-
ature for each month at the several stations and

shows a great difference between Gram waven ard

the western cities during the summer months, also

in the spring and early autum, Gram Haven being
cooler during this period by 6 to 10°F, The

average minimum temperatures reached daily for the
various months are tabulated in Table III, bringing

out the fact that extreme cold is not felt at Grand
Haven as it is in the West, away from the lake.
Throughout the winter the difference ranges from

9° to 11°F, But the most pronounced effects are
shown in Tables IV and V which give the highest am lowest

ever recorded, respectively, each month in the year.
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These tables show that the extremes of temperatbre
experienced at inland stations are not felt at

Grand Haven, which is a typical lake station.

As already stated the frequent passage of
cyc lones am anti-cyclones across the Jake region
causes fluctuating temperature to a greater extent
than is found in regions outside the storm path.
In the winter season the approach of a storm area
from the west is preceded by southerly wind and rising
temperature in Michigan, and the high pressure area
which follows brings with it a shift of wim to the
northwest, with colder weather. In the summer season
storm areas which move across the northern portion ¢
the Great Lakes, at a time when the pressure is high
over the southeastern states, cause hot waves in this
state, but these are usually followed ina day or
two by refreshing northerly breezes attending approeahing
high pressure areas from western Canada. The
changeab leness of the temperature is therefore one of the
noticeable features of the climte of Michigan.

Precipitation.

Rain and snowfall should be next considered.
The same four factors which control the temerature
of a place also influence, to a greater or less extent,
the amount of precipitation. The influence of

Jlatitude is not so pronounced on precipitation as on
temperature. In fact within the range of latitude foun

in Michigan no difference in rainfall due to distance from -
12

the equator is noticeab le,
The effect of elevation is noticeable, however,
prehaps to a greater extené than on temperature.
Chart VII, showing the normal precipitation for the
year over the state, if noted in connection with
Chart I, giving elevations, reveals the fact that
rainfall usually increases with altitude,.as a
general rule. This is especially true on the
western slope of higher land. For example the
heaviest rainfall in the state is in the southern
tier of counties, beginning about 25 miles from the
lake , where the elevation begins to increase toward
the eastward. In the upper peninsula the most rain
falls in the interior counties, where the elevation
is greatest. In the elevated regions in the northern
portion of the lower peninsula, however, the rainfall
is not greater than nearby sections having Jess altitude.
The Great Lakes undoubtedly increase the rainfall
theoughout this whole region, but the annual amount of
pregwipitation is not noticeably greater on the immediate
lake shores than further inland, Such large bodies of
water furnish much vapor to the atmosphere, which is
carried upward by convection with each cyclone which
passes, is cooled, condensed and precipitated as rain
or snow, In the lake region the annual rainfall is
over thirty inches, while in the Dakotas it is less
than twenty inches,-w differencedue partly at lease

to the lake effect. The reason for even less rainfall
r

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13

immediately along the shores of the lakes, than in

some interior sections, mav be the fact that tie cooler
weather near the lakes in summer does not foster the
convectional action and local thunderstorms to the

extent that the warmer interior regions do. The average
number of thunderstorms per year at Grand Haven, Mich.

is twenty-six, while at Lansing the average is forty-two.
The snowfall is considerably greater near the lakes, however,
especially along the southern coast of Iake Superior arm
the eastern coast of ,yake Michigan. In the former section
over one hundred inches of snow usually falls each winter,
as shown in Chart VIQ, Along the shore of Lake Michigan
from fifty to sixty inches per year is the average, but in
the interior of the state the snowfall totals from thirty
to Sifty inches annually, in most sections. In the
rorthern portion of the upper peninsula the showfall éxceeds
‘one hundred “incleés afnually, This heavy snowfall along
-the Jakes is caused by the passage of the prevailing west-
erly winds, first over the comparative ly warm water of
fakes Michigan and Superior, for distances of sixty to
over dne hundred miles, causing them to become moisture
Jadened, and then on coming.::: in contact with the

cold land areas along the shore the mogsture is condensed
and falls as snow almost continually, at least while the
winds continue on shore, during the winter season.

he ground is usually covered in the lake Superior

region, with one to five feet of snow, from middle

autum to late spring.
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14.

The fourth factor controlling climate, i. e.
the proximity of the normal storm path, is a very
important one as regards rainfall, Ordinari ly
each successive low pressure area brings more or
jess rain or snow as it paases over Michigan; and
the precipitation is therefore ample and well
distribtted through the. year. Chart “IX. brings
out this matter of distribution in difference portions
of the state, as well as graphically showing the amount
of rainfall available in each place.

Cloudiness.
The amount of sunshine is an important element

in climate both on account of its relation to crop
growth ani deve lopment and the’ general wellfare ani
happiness of mankind. It probably ranks next after
temperature and precipation, in importance,

Like precipitation the range of latitude found
in Michigan has no appreciab Je affect on ‘amount of
cloudiness, but on account of the fac t that the
possible hours of sunshine increases, during the
summer season, with distance from the equator, the
fact should be noted that the davs are ‘more than thirty
minutes longer in summer in the upper peninsula than |
in the southern portion of the lower peninsula.

The range of elevation in Michigan is hardly

sufficient to cause an appreciable difference én the

amount of cloudiness tut the influence of the Great

Lakes is decided, As wes explained in connection with
15.
discussion of precipitation, the warm, moist air over
thé Lakes in winter, is carried land-ward by the prevailing
westerly winds, and clouds are continuously formed when
the colder lund areas are reached, by condensation.
The weather is therefore unusually cloudy in Michigan
during the late fallam winter months, especially in
the western half of the lower peninsula. In fact with
the exception of portions of New York state ,‘.alon> the
eastern end of yake Erie, am in the eastern portion of
the upper peninsula of Michigan, there is less sunshine
along the Jake Michigan shore than in any other section
of the country. In January the actual sunshine in
western Michigan is less than twenty per cent of the
the possible amount.

During the warmer portions of the year, however, \
the Great Lakes have just the opposite effect. The
cool water tends to prevent convection and clouds are
not formed to the extené that they are in warmer sections.
As a.result the amcanf'dsunshine is therefore greater
in July, by about ten percent, in western Michigan than
it is in Ohio am Indiana.

The alternate passage of areas of high am low
pressure over the state results in fluctuatine cloudiness.
Low areas usually cause more or less cloudiness for one
or two days during their approach and passage am these

are f@llowed by two or three days of clear weather, as

the anti-cyc lones pass over. This change from cloudy to

Clear weather and back again is not noticeable in the

4
oP ete!
16
winter season to the extent that it is in summer on
account of the almost continuous cloudiness caused
by the idkes. In the summer time the cyclonic ard
anti-cyc lonic formations often become so feeble
that they fail to cause the changes in cloudiness am

there are long periods of uninterrupted sunshine.
These features are clearly shown in fable VI ,herewith.

WIND
The wind direction and velocity are important

largely on account of their relation to the other
climatic elements. The direction of the prevailing
winds, for example, is especially important in this
state on account of the position ofn the Great ypkes.
If they wege east instead of west then it would te
the ;yake Huron shore that would have the more equab le
climate.

Miicrhigan is, of course,in the region of the
prevailing westerly winds. Chart X .. shows the
prevailing direction at each observing station in the
state. Local influences such as the contour of the
Jand and the proximity of the Lakes causes sone
deviation from the true west, at some stations.

The "land am sea breeze" is pronounced along the Jake
shores. This ds a local wind, blowing on shore in the
heat of the day and toward the water at night, due to
convection, The air becomes hot and lighter over the
Jand than over the water on a hot summer day, ami the
cooler ani heavier air over the cool water moves in ,

forcing it upward. Just the opposite action takes
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place at nisht, when the lund becomes cooler than
the lake. Trese cool, refreshing lake breezes are
very welcome on a hot surrer afternoon, but in the
early spring thev are often too cool to be pleasant.
The temperature often falls thirty degrees or more
within a few minutes when the wind shifts on a warm
spring afternoon,armd blows in from the cool lake.

As has alreaiv been stated the passage of
areas of low and high pressure across the Great
Lakes region is attended by shifting winds. The
currents of air flow spiraily inward toward the centers
of lJow barometer, counterclockwise, while in the
high pressure areas the winds blow syirally outward
from the center, in a clockwise direction. Vhen
a@ cyclone approaghes from the west, therefore, the
winds are first southeasterly, shifting around either )
through east and north, or through south ani southwest,
depending, of course, on the path the storm takes, |
changing in the former direction if the storm passes
south of the observer, and in the latter direction if
the center is to the northward. With the oncoming
high area, if it advances from the rrthwest, the
winds are northwesterly. With a good aneroid barometer
am wind vane the movement and passage of these
atmospheric formations can be determined ard followed
with interest ard profit, for they largely control

weather changes.
18.
Humidity.

Tre amount of moisture in the atmosphere in the
form of vapor is important enough to be classed in
with the other climtic elemnts. It is usually
expresséd in terms of relative humidity, or the
per cent of motsture present in the air, compared
with the possible amount. The capacity of the air
for moisture increases rapidly with the tempereture.
For example the invisible vapor necessary to saturate
air at 40°F. is sufficient to produce a relative
humidity of but 50 per cent when the air temperature
is increased to 60°F,

Of the four factors which control dlirate ondy
the Jast two need to be mentioned here in their
relation to humidity, because neither the range of
latitude or altitude fourd in Michigan is sufficent
$0 appreciab ly change the humidity. Eut the presence
of the large water surfaces of the Great Lakes
is an important factor in influencing the humidity,
because such surfaces are constantly evaporating
weter into the atmosphere. The following ta le will
serve to show the effect of the Great Lakes on relative
humidity:

Jan. Feb. Mar. Apr. May June July Avg.
Jansing, Mich. 8&5 &0 74 68 68 Fe AY 73

Bismark, N.D. 66 67 65 55 54 59 oP 49

Ssept.Oct. Nov. Dec. Year.
Lansing, Mich. 80 8l 80 85 76

Bismank, N.D, 52 60 63. 67 59

TABLE MI. Relative humidity at Lansing ,Mich. ani Bismarck,
N.D. at 7 p.m, by months am for the year.
19

Part of the difference in relative humidity between
the two stations in the table is probably due to
the fact thaé Bisrarck, N.D. is some distance fpom the
normal storm path, while Iansing, Mich. is more directly
in the region most frequently traversed by "highs"and "lows?
An increase in cloudiness and rainfall, brought about
by the passage of low pressure areas ,aliso causes an
increase in relative humidity.

Other Phenomena.

There is yet to be considered the occurance of
other atmospheric phenomena sich as hail, frost,
tornadoes, etc. Thepe are more or less destructive to
farm crops and their discussion will properly fall
in what is to follow. But a word should be said
as to their dsitribution and frequency over the state
before the subject of the relation between the climate
of Michigan and agriculture is taken up.

Hail is an attendent upon heavy thunderstorms.

It is very local in character, covering only small
areas in any particular storm. On the average two
hailstorms per year occur at lansirg, which my be
considered a typical station for-interior Michigan,
but the number is Jess near the lake shores.

Frosts occur each fall and spring, the dates
being largely influenced by the first three factors,
influencing climate, i.e. latitude, altitude, and
proximity of the lakes. The fourth factor should

also be considered, but. somewhat modified.
20,
latitude of course is an important factor in determining
how late in the spring am early in the fall killing
frosts are liable to occur, In the interior of the
upper peninsula the weather remains cold until asarly
summer ami the period of warm weather is short, while
in the extreme southern portion of the state it is
much warmer, A table is appended giving the dates
of frost ari the length of the growing season at many
stations in the state. From this table the following
is extracted to illustrate the mtter of the effect of
latitude on dates of frost.

Station LTatitude Average date Average date Average length
last killing first killing of growing
frost in spring frost in fall season.

Humboldt ,46°30! June ll August 27 77

Adrian ,4 1°50! May 7 October 25 171

Elevation has some bearing on the length of
the growing season, but the mtter of air drainage
asp affected by local influences is more important.
A station on a hill side, which allows the cold air
+o drain off into a valley below, will escape frosts
longer that a place <situated at a lesser altitude.
The proximity of the Jakes ras a pronounced
influence in preventing early frosts in the fall.
At Frankfort, on ake Michigan, the average date of the
first killing frost in autum is October 19, while at
Grayling, about the same distance north, but in the
interior of the state the average fall frost is more

than a month earlier, Table VII and charts XI,XII and XIII
show the dates of frost ani the length of the growing season .
20 (a)

Petes of killing frosts and length of growing season

UPPER PENINSULA.

 

 
   
 
 
   
  
    
  
 
 
  
    
  
  
 
 
   
    
   
  

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Barage, Baraga Jun.2

Calumet, HoughtonMay 3
Chatham, Alger Jun.2
i. Harbor ,KeweenawJun.

Escanaba,Delta July
Gd.itarais,Alger June

Houghton, oushtoniiay 2
Humboldt ,i'q't. Jun.2
Iron Mt, DickinsonJun.
Ironwood ,GoegebicJun.
Iron River,Iron Jul.2
Ishpeming,ii'g't. Jun.
Mackinaeé Island Jun.2
Maple Ridge, DeltaJun, 27
Liarquette, li'q't.Jun.1
“enominee ,M'nee Jun.2
Newoerry, Luce Jun.2
Stignace, JiackinacJun. 28
5.5. Marie ,Chippewa:iay28
Whitefish Pt. ,do May28a

NORTHERN COUN
Alpena, Alpena Jun. 9
Benzonia,fenzie iay 27
Charlevoix, C'v'x.Junl
Cheboygan,C'bd'n. Jun.2
Kast Tawas,Iosco Jun.24
Frankfort ,2enzie ‘fav 27
Grayling,CrawfordJun. 8
Herrison,Clare May 3
narrisville ,AlconaJun2
Ivan, Otsego Jun, 12
Ludington,iiason Jun. 1?
iackinaw,Chebd'n. Jun.20
dance lona,Antrim Julyl3
wanistee ,lianistee.fay 28
Old Mission,Gd.T.Jun. 9
Omer, Arenac Jun, l2
Onawa,Prisque IsleJun.
Reed City,%sceolaJun. 1?
Roscommon,Rosc'n Jun.25
St.J-mes,C'v'x. Jun. 9
Traverse Cy.Gd.T.iay 3
West Branch,OgemawJun24

> Earliest date of
& killing frost in

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146
45
151
125
131
162
121
138
139
140
144.
137
117

160
119
121
124

90
149
143
124

 
20 (vb) .

Dates of killins frosts and length of growing season
(Continued )

CENTRAL COUNTIZS, LOWER PENINSULA.

 

 

 

 

 

 

 

 

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Alma, Gratiot May 28| Sep. 2/May 1l2|Sep. 29 | lO

Arvela, Tuscola Jun. 9| Aug.27 |iiay Jl2|Sep. 23 | 134

Bay City, Bay May 271) Sep. 18|/iiey 9 |Ocet. le | 157

Big Rapids, liecosta May 29] Sep. 2|/May 13|/Sep. 23 | 133

ilarbor Beach, Huron Jun. 4|Sep.J7/liay i1)Oct. 8 | 150

Nart, Oceana May 28|Sep. 2|lay 13/Oct. 8 | 48

Muskegon, Muskegon — May 27|Sep.14|May 7/Oct. 8 | 142

Port Austin, Huron Jun. 20] Sep, lOjMay 16)/Oct. 3 | 1A0

Saginaw, Saginaw May 28] Sep. 4/May 5/Oct. 7 | 155

Southern Counties , Lower Peninsula.

Adrian, Lenawee May 28;Sep.19;May 7/Oct. 25 | 171

Allegan, Alle gan Jun.,llj/Sep. S5|May 13/Oct. 9 | 149

Ann Arbor, Washtenaw May A|Sep.22|May 4/O0ct. 16 | 165

Battle Creek ,Calhoun May 27| Sep. 19/liay 3/Oct. 9 | 159

Bloomingdale ,Van Buren May 27|Sep.12|May 8/Oct. 10 | 155

Cassopolis, Cass May 27|Sep.22|May 3/Oct. 13 | 163

Coldwater, Branch fay 21) Sep.18|/May 3/Oct. 6 | 156

Detroit, Wayne May 31) Sep.2l}Apr.29/O0ct. 13 | 167

Hloise, Wayne May 27|Sep.18|lay &8)/Oct. 9 | 154

Flint, Genessee Iay 27|Sep.18|/May 9/Oct. 7 | 151

Grape, Monroe May 28|Sep.19|May 7|/Oct. 13 | 159

Hastings, Barry May 28|Sep.18|May 15|/Oct. 4 | 142

Hillsdale, Hi llsda le May 28]Sep.19|May lO/Oct. 6 | 49

Holland, Ottawa fay 27|Sep,26|May 9/Oct. 9 | 153

Howell, Livingston May 28|)Sep.19|May 8/Oct. 7 | 152

Jackson, Jackson May 21|Sep.18|‘lay 3/Oct. 10 | 160

Jeddo, St.Clair May 28|Sep.22|May 7/Oct. 15 | 161

Lansing, Ingham Vay 28|Sep.19|May 4/Oct. 9 | 158

utClemens, Maconb May 31|/Sep.19/May 13/Oct,. 10 | 150

Owosso, Shiawassee Jun. 8|/Sep. U|May 13/Oct. 4 | 46

Plymouth, Wayne May 28|Sep. 2j/May 7]/Oct; 3 | 149

Pontiac, Oak land May 29|Sep.i11|/May l1/Oct. 10 | 152

Port Huron, St.Cilair Jun. 6|Sep.22|May 6/Oct. 10 | 157

South Haven, Van Buren May 20|Sep.21|liay 3/Oct. 13 | 163

Ypsilanti, Washtenaw May 29|Sep. 14|May 1O/Oct. 6 | 149
TABLE VII. Showing the dates of killing’frosts

in spring and
autumn. The average dates are computed from long series of
years, in some cases as many as 43. Length of growing season

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a1.

Tornadoes occur infrequently in Michigan, on the
average about one or two per year in the entire state.
They are practically unknown in the upper peninsula.
The region of most frequent occurance is in the south -
central portion of the state. The Great lakes
undoubted ly decrease the number somewhat, on account of
their cooling effect, therby checking the required
convection. These destructive local storms occur
usually in the southeastern portion of the larger
disturbance, or cyclone, and as the state is in
the path of greatest frequency of these cyclones,
it seems reasonable to suppose that tornadoes woud
be more frequent in Michigan than in other states
cutside the path of storms, were it not for the
Great yakes.

Notab le tornadoes, in recent years, were
two which occurred in 1911 and 1915 respectively.
The first passed through the city of Owosso, doing
considerable damage and causing some loss of life.
The second passed southeastward from the city limits
of Charlotte, Mich. passim two miles north af Faton Repids,
to some inland lakes southeast of Stockbridge, Mich. ’
where it disappeared. This storm was of unusual
severity and leveled everything in its path. Had it
passed through any city it would have caused great
loss of life and greater destruction to property.
High winds occur at intervals in connection

with thunderstorms, of sufficéént strength to do
22
serious damage, but the stxte is still fairly well
wooded am sufficiently rolling to check the wird
velocity to a considerable extent. High winds are
frequent on the Great Lakes, in connection with
marked cyclonic formations, but their velocity

is lessened as they come inland.

PART III
The Relation of the Climate of Michigan to Agriculture.
Climate and agriculture are closely related bacause
ail crops require certain amounts of heat, moisture am
sunshine to make normal growths. The exact requirenents
of any crop for any given climatic condition are very
difficult to determine ani state in figures, because
the relationship is complicated and plants are able to
a degree to overcome unfavorable environment. PBrobably.
no exact statement has yet been made as to the most
favorab le temperature conditions, for example, under
which a crop would thrive best, or how many heat units
are necessary for any crop plant to perform its life
functions to the best advantage. There have been
numerous attempts to find a "thermal constant", as it
has been called, for various crops, in terms of air
temperature during the life phase of anv crop, under
the supposition that a uniform quantity of heat is
necessary to produce a given increase in growth. But
results

widely different mmm are found from year to year when

daily air temperatures are added together over a period

during which the plant is passing through a certain
203

growth stage. Somewhat closer results are obtained vy
subtracting a constant amount, usually 42, from tach

&ir temperature considered, because 42°F, may be *consider-=
ed as zero for plant growth for ordinary farm crops.

This process of adding together the remainders after
subtracting 42 from each daily temperature reading, has
been called the "summation method" of studying the re lation
between air temperature am plant growth. As stated

above it does not give consistant results.

2 » serend auer®

Livingston » am others have intro-
duced van't Hoff's law, to the effect that chemical
action, and hence plant growth, which is largely
chemical in nature, is accelerated ami doubled with
each increase of !8°F in temperature, into the
prob lem. This system seems to hold good for medium
temperatures, am givesciloser results than the summation
process, but it fails,as does the latter also, when higher
temperatures are concerned, because it take no account of
the fact that the rate of growth decreases after u certain
temperature is passed.

To overcome this defect end to further perfect
the system, Livingston? has worked out a series of values
or indices of growth corresponding to each degree of
tempe rature. These indices were determined from Lenren-
bauers”’ -¢unve of growth in mize seedlings as controlled
vy temperature. He took the rate of growth at 40°F as
unity and found values for each succeeding temperature

on this basis, The highest value was 1°2 at 89°F, after

Which the indices rapidly decreased to unity again at l16°F,
24

When this system is applied to wir temperatures
it gives slight ly better results for the earlier
growth phases, but seems to be no improvement over
earlier methods for later periods of growth.
Seeley® has pointed out that the temperature of the
plant itself is widely different than that of the air
which surrounds it, especially when the sun £s shining,
and suggests that plant temperatutes be used instead of
air temperatures in studims of plant growth. He found
that plant leaves were, on the average, 15°F warmer
at midday, in clear weather, than the air temereture,
1O°F warmer when the sun was partially obscurred in
partly cloudy weather, and practically the same temper-
ature on cloudy days. These averages were obtained
from over 300 observations made during the growing season
of 1915 and 1916. we proposes a formula for evaluating
air temperatures in terms of the true.plant temperature
as-follows: -- T= t -42 N +15 C +10 P, where "t." is
the sum of the daily maximum temperatures durirg a given
period, "N" the nunber of days in the period ,"C"the
number of clear days am "P" the number of partly c loudy
days. Applying this formula to the average temperatures

at a number of stations in Michigan, using the normal
numer of clear, partly cloudy am cloudy days during the
growing season, in each section, gives a more accurate
idea of the true thermal conditions under which crops

srow in this state. Chart XI°V shows the results obtained

in this way. It will be noted that the Jargest value, 7183

is about 40 per cent greater than the least value ,5048,
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25

the stations having these values being, respectively,
Adrian, in the extreme southern,interior, portion

of the state, and Calumet, in the extreme north am on
fake Superior. It will be noted that the interior of

the state has much higher termal values than sections near
the lakes.

With further stady am research accurate methods
will probably be evolved for defining the suitibility of
the temperature in any section to meet the plant requirements,
but at present onlv the most general terms can be used.

The ceréal crops grown in Michigan more or less extensively
are corn, wheat, oats, barley and rye. They each find
temperature conditions to be a limiting factor, toa
greater or less degree, in the production of a maximum
crop in a rather large per cent of years.

Corn is grown to a considerable extent in Michigan,
especially in the southern portion, but at least in the
northern portion it is not gro-n as successfully as it
is in the "Corn belt" states. The plant requires a
ruther long frostiless season, with warm nights for best
resuits,and theee conditions are not found in the northern
portion of the state. The crop will mature in 100 to 120
days when the weather is sufficiently warm, but 120 to 2130
days are necessary to ripen it well if the weather is cool,
Referring again to 6harts XI, XII and XIII, showing frost
dates and the Jengt: of the frostless season in various

s

sections of ichigan it will be seen that many portions of

the stute are unsuitable for corn,
26

The winter varieties of wheat are grown exc lusively
in Michigan because there is usually sufficient snow to
protect the crop through the winters, which are not so
severe, as has been pointed out, as those in the Northwest.
Some“winter killin# occurs Jargely an account of alternate
freezing and thawing when the ground is bare, but on the
average the yield is satisfactory. The same statements
apply to rye, which is also sown in the fall,

Oats and barley seem to find suitable temperature
environment in nearly all portions of the state, amd goad
crops are usually obtained where the soil is suitale.

Other crops which are successfully grown in Michigan
on account, in a measure, of favorable temperature conditions,
are huv, potatoes, beans, sugar beets, cucumbers, peas,
chicory, mint am various other minor crops. It is
doubtful if any other stute in the union has a wider
range of crops of rather Jarge proportions than this state,
Jarge ly due to the combination of murine am continental
temperature conditions of this state and the local variations
of other climatic elements as well, which have already been
noted.

Fruit is a leading product of Michigan, largely on
account of the very favorable climatic conditions produced
by the Great lakes. A narrow strip of the state extending
along lake Michigan is especially adapted to fruit and has
been given the name of the "Fruit Belt" because of this fact,

Among the climatic conditions found in this section that are

favorable to fruit growing are, firs’, the continuation
Of cool weather into late spring which tends to retard
27.

the opening of fruit buds until dunger from late frosts
ie past; second, unusually clear am not too hot summer
weather, which produces good color ani flavor in the fruit;
third, prolonged cool falls, with freedom from early frosts,
which tends to ripen up the wood properly, and, fourth,
a moist atmosphere and freedom from extreme cold in winter
which prevents winter injury. The fruit industry is still
in its infancy in this favored section, but growers are
beginning to realize the possibilities of the region.

The precipitation which normally falls in Michigan
is sufficient for the crops which have been mentioned. But
here again statements of exact relationships are as yet
impossib le, Briggs am Shantz® have worked out the actual
rainfall requirements to produce a pound of dry weight in
corn and Smith? has found that the yield of corn, potatoes
and other crops is largely a matter of securing the required
amount of moisture during certain short critical periods .
Investigations in Italy and Russia ltve indicated that
wheat also has a "critical period" during which the yield
is determined by the amount of rain then available,
But much more work must be done before the rainfall efficiency
for crops can be stated for anv section.

In general it is important that the precipitation
for the year should be am le, and also tmt it shoud be
suitably distributed through the months so that a sufficient
supply will be available when the crops are growing and

maturing. Reference to Chart 2X. shows that the most rain

falls from May to September, in all parts of the state,
 

DEPARTMENT OF MAI?
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28

and these are the months that it is most needed.
Chart XV shows the distribution in Michigan compared
with that in other portions of the country, by

which it will be seen that an equally satisfactory
distribution does not obtain in all other sections.
Occasional droughts occur in portions of the state
which seriously shortens yields. One of the most

serious of such droughts was that of July am August,

‘19 16, which mrkedly reduced the crops of corn,

potatoes, beans, sugar beets am other crops in

most portions of Michigan. This affords a good
opportunity for studying the relationship between
precipitation shortage ani crop shortage, and

Chart XVWhas been constructed to vring out this

re lationship. It will be noted that the yields of
corn and potatoes are directly proportional to the

July rainfall. With the exception of potatoes in

the northern portion of the lower peninsula the length
of the lines representing the crop yields are in

the same proportion as the lines representing rainfall in
July, and this discrepency may be accounted for by the
fact that in the heavy potatoe producking counties in
this northern section, along Lake Mictigan, the rainfall
was much heavier than that in the interior of the state and
the eastern portion. The average yield was there fore
enlarged in those sections thereby unduly enlarging the
general average. In lee:linau county, for example, the

fainfall for July was about two inches ard the average
9.
yield 130 bushels per acre, while in Kalkaska County
nearby, the rainfall in July was little over half an
inch, amd the yieldd of potatoes but 20 bushels per acre.

The yield of beans seems to be less closely re kAted
to the July rainfall than the other two crops mntioned,
but a closer study indicates that rainfall in August in
a determining factor on thé ybeld of this crop. The
average July rainfall in 1916 in ten counties which had
the Jargest yield of beans per acre in the state Just
fall, was 0.96 inches am the August rainfall in the
same counties 3.26 inches, while in the ten counties
which yielded the least the July rainfall was about the
same as in the other ten, -0.88 inches, but the August
rainfall was only 2.02 inches, or more than a third
Jess than fell in the ten counties yielding the most.

The more or less even distribution of rain over the
growing season,:and in sufficient amounts, is therefore
an important consideration where such a variety of crops.
are raiseé.

In at: Jeast two respects the unusual amount of
cloudiness near the windward shores of the lakes during
the winter season, mentioned in Part II, has an important
vearing on agriculture. Ore of these is tre beneficial
and protective influence on fruit trees over winter, as
stated. Were it not for this cloudy, moist atmosphere
injury would more often result, as it does in other sections,
from drying out of the wood. Second, cloudiness prevents
thawing of wheat and rye fields on winter days, which is

injurious when followed by freezing at night.
  
  
 

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Total annual precipitation ard mean annual temperature |

 

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Temperature F°
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Degree of

at Lansing; Michigan, 1864 to1916 inc lusive.
(Precipitation in black, temperature in red, )

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30,

On the other ham the larger nunber of clear daysover much
with

of Michigan in the summer season, as compared Ww adjoining

States is a decided advantage to practically all crops,

but especially to sugar beets ami fruit, producing not
oniy larger crops but of better quality.

The direct bearing of wim velocity am direction
on crops is slight am difficult to trace, but indirectly
these elements play an important part as thev largely
influence the other atmospheric conditions.

The occurance of peculiar phenomena, such as hail,
tornadoes, torrential rains etc. cause more or less destruction
to crops. They are all local in character and hardly need
be discussed here. The aggregate loss to farmers from these
severe weather conditions is not large, but individual losses
are somptimes heavy.

Just a word should be added to the effect that the
climate is not changing, am therfore favorable or unfavor-
ably affecting agriculture. liny persons seem to believe
that the climate is different now than it was a half century
ago, but a careful study of accurate records mate for long
periods shows no change in average conditions. Chart XVII
was constructed from records begun in 1863 at the Michigan
Agricultural College, by Dr. R. C. Kedzie, and carried on
vy him for nearly forty years, with almost no interruption,
and continued since his death bv other observers. This chart
shows irregular fluctuations from year to year, but no
permanent change, or tendency to change in any direction.

The average of any ten consecutive yearé' records, during the
31.

period, either of rainfall or temperature , will be found
to be about equal to that of any other period of equal
Jengtnh.

SULuLARY.

The purpose of this paper is to describe the
climate of Michigan, am explain its peculiarities,
and then to correlate the climate as described
with the agriculture of the state.

The influences which control climte are
four, namely latitude, altitude, environmental
surroundings and tne location relative to the
normil storm paths.

The temperature decreases in this and other
sections about one degree per one-hundred miles in
distance away from the equator. A rise of about
300 feet in elevation causes a drop in temperature of
about 1°F. “The presence of the Great yakes causes
marked differences in the climate of Michigan as
compared with other sections. The windward side of the
lakes have a much more equable temperature, more snowfall
and c Joudiness in winter and more sunshine in summer,
than interior regions. The fact that Michigan is in
the direct path of cyclones and anti-cyclones results
in frequent weather changes, more precipitation which
is well distributed, am invigorating veether conditions

generally.
On the whole the @limate of lfichigan is not extreme

in temperature, either in summer or winter, the rainfall
ms

38

is sufficient for most crops, the most of the year's supply
falling during the growing season; the cloudiness is
greater in winter and less in summer than in regions remote
from the Great Lakes; the humidity is rather high throughout
the year, especially on the Jake shores; the prevailing
winds are westerly, often high on the lakes but decrease
as thev pass inland. Severe local phenomena such as
hail, tornadoes, torrential rains etc. occur infrequently.
The usual cereal crops grown in the central

valleys are raised in Michigan. Corn can be grown about
as successfully in southern Michigan as in the "Corn Belt",
but the seasons are often too short in the northern
portion of the state to mature the crop. Wheat, oats,
rye, varley, potatoes, beans, sugar beets, are all
important crops, while many minor crops are also produced.
There are localities where each seems to find particularly
favorabd le climatic conditions in the state, which has an
unusually wide variation in climate. The "Fruit Belt" alon g
the Jake Iiichigan coast is pecularily adapted, as to climate
for growing fruit on awount or its cool springs, moderate
summers with much sunshine, late falls and mild winters with
much snow am cloudiness.

The climate is not changing as shown by a study of
over fifty vears of records made at the Michigan Agricultural

College.
Page 38

Literature cited,

l. Eshleman, C. H.- Clim.tic @ffect of the Great I-kes
as typified at Gram waven, Mich. Pamphlet issued
in 1913.

2.Llivingston, B. HB. and Grace J. -Temperature Coefficients
in Plant Geography and Climatology." bot. Gaz. No.56,
pages 340-375, 1913.

3,lerenbdauver, P. H.=-"Growth of waize Seedlings in Relation
to Temperature." Phys. Reasearches., Vol.I, No.5, 1944.

4. Livingston, B. E.=- "Physiological Temperature Indices
for the Study of Plant Growth in Relation to Climatic
Conditions." Phys. Researches, No. 8, April,19 44.

5.lerenbauer, P. H.-(Sam as "3" above. )

6. Seeley, D.A.-" The Relation between Temperature ami Crops"
Peper read before the ltichigan Academy of Sciences,1917.
(Not yet pub lished. )

7.£riges, L.J., and Shantz, HL. "Relative water Requirement
of Plants". Journ. Agr. Research, 3: 1-43. 1914,

&, Smith, J. Warren,-"Effect of Weather on tie Yield of
Potatoes", Mo. Wea. Rev., 1915. Pages 222 to 223.

"Correlation between Crop Yield ani Wecther" Wo.
Wea, Rev. 1911, Page 792.

"Effect of Weather on the YiewR of Corn". Mo. Wea.
Rev., 19144, Page 78, Also other attic les.

The meteorological data used in this paper were extracted
from pub licatiorpof the U. S. Weather Bureau, largely

Climatological Reports, Michigan Section, also Bulletin
"Q8, Climatology of the United States, U. S. weather
Bureau, 1906. Figures on crop yields were taken from
the Michigan Crop Report, 1915-16, published by the

Secretary of State, Lansing, Mich.
33 (a)

Location of Observing and Forecast Distributing Stations.

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