August weather forecast and climate
Illinois, USA

Flag of Illinois, USA
Flag of Illinois, USA

Weather in August

August is a hot and humid month in Illinois with long daylight hours and many sunny days. The average high temperatures reach up to 88°F (31.1°C), with the highest temperatures in central and southern Illinois. The northern regions have relatively mild temperatures by a few degrees and comfortable nights. Moline in the north registers temperatures in the 63°F (17.2°C) to 84°F (28.9°C) range. The sunny days and clear night skies offer the best time for camping and stargazing in the state parks.
Summer rainfall is to the tune of 3" (76mm) to 4" (102mm) statewide. The peak of the tornado season is over, but thunderstorms and occasional tropical cyclones are still at work in August.
Light summer clothing is comfortable during hot days, as the perspiring body cools faster in a sweatshirt. Lakes are hot spots during the summer as the proximity to the water brings a refreshing coolness to the atmosphere. August is an excellent time to visit Illinois for people who can bear the summer heat.


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