Geographic Regions in Indiana 99 



SOME CONTRASTS BETWEEN GEOGRAPHIC REGIONS 



IN INDIANA. 



Stephen S. Visiier, Indiana University. 



Indiana is strikingly unifoim in msny ways. There is comparatively 

 little regional difference in rainfall, in tempciature, or in altitude. 

 Nevertheless, minor contrasts occur in Indiana in respect to many geo- 

 graphic conditions and have several significant effects. 



Some of the contrasts which may be mentioned are those of climate, 

 of types of soils, of altitude, of relief, of drainage conditions, of rela- 

 tions to waterways and railways, differences in farming practices, in 

 chief crops grown, and in the conveniences and equipment in and about 

 the farm home. 



Temperature Contrasts. There is an average difference of about 

 5° F. between the southwestern corner of the state and the northern part, 

 a difference of nearly 6° in summer and 8° in the maximum tempera- 

 tures. The northeastern corner never has had an official temperature 

 above 103° while the southern part has had a temperature of 111°. The 

 sectional differences between the lowest temperatures ever recorded is 

 somewhat less. The lov/est is 33" below zero at Lafayette, while a 

 temperature of 28° below has been officially recorded from Paoli and 

 Jeffersonville. These differences in temperature are due chiefly to the 

 differences in latitude, but are partly due to differences in altitude, 

 the southwest corner of the state being within 350 feet of the sea level, 

 while the northeast corner is above 1,000 feet. 



The growing season, or the period without killing frost, in the 

 southwest third of the state usually is nearly a month longer than in 

 the northeastern corner. However, the frost-free season near Lake 

 Michigan is, on the average, a week longer than somewhat farther 

 south. The lake is comparatively warm in the autumn. Spring frosts 

 occur near the lake as late as they do farther away but they do less 

 darnago to fruit trees because the cold winds from the lake and the 

 cloudiness prevent early growth. 



Contrast ii iu Rainfall. There are two chief types of sectional con- 

 trast in rainfall. The southern part of the state receives several inches 

 more per year, but a larger fraction falls in the cooler six months than 

 is the case in the northern part of the state. In the southei'n half of 

 the state the average rainfall is 40 to 45 inches, while in the extreme 

 northwestern corner of the state only 33 inches are received. In gen- 

 eral, each month of the year receives about three inches of rain, but in 

 the northern half of the state, about 55 per cent of the year's total 

 falls during the warmer six months, while in the southern part of the 

 state 50 per cent is received in that season. In the extreme northwest, 

 60 per cent of the precipitation comes in the warmer season, when it 

 is most needed. The decrease in rainfall northward is related to the 

 increased distance from the Gulf of Mexico, the one great source of 

 rainfall for Indiana. The larger percentage in summer to the north 

 is related to the fact that in winter, moisture carried northward by 



"Pron. 38th Meeting, 1922 (192^)." 



