Like much of the east central part of the United States, Indiana has strongly marked seasons. The climate is distinguished by high humidity, much rainfall, and moderate cloudiness and windiness -- characteristics due to the State's position in the mid-latitudes and in the path of moisture-laden winds from the Gulf of Mexico.
Although occasionally Indiana experiences severe winters with protracted below-zero weather, normal winter temperatures hover near 28° or 30° F. Freezing night temperatures and daytime thaws are characteristic throughout the cooler part of the year. The consequent contraction and expansion of surface soil sometimes breaks the roots of winter grains; but the long periods of moderate coolness are favorable for 'stooling' -- the development of multiple stalks from one seed. Indiana summers are hot, with warm nights and temperatures during the day frequently approaching 100°. The growing season averages 170 days.
The average annual precipitation throughout the State is 40 inches, distributed fairly evenly throughout the year. Some years, however, bring drought, especially in the southern hills; while others bring extremely heavy rains. Of the annual precipitation only one-fifteenth, on an average, is snow. Gales are rare, the average wind velocity being only eight miles per hour. Infrequently there are tornadoes.