:. Illinois Weather And Climate .:

Illinois weather varies depending on how far north or south you are visiting. The northern climate is colder in the winter, cooler in the summer (but still often fairly hot and humid), and a little drier than the southern part of the state. These variations aren't spectacular, the north gets about 35 inches of precipitation per year, while the south gets 48 inches. The north gets 38 inches of snow, while the south gets 14 inches.

Thunderstorms are common but not excessive. Tornados are the greatest threat to Illinois, with some of the deadliest in US history occurring in the state over the years.