<p>Illinois has a humid continental climate with hot summers, cold winters, and frequent winds. Autumn is the most popular time to visit, bringing mild, comfortable temperatures (15-20&deg;C) and colorful scenery, with only the occasional late-season thunderstorm. Summers are warm and lively, perfect for outdoor activities and festivals, with temperatures around 27-30&deg;C. Winters are cold, especially up north, with January temperatures around &ndash;6 to &ndash;1&deg;C and 10-50 inches of snow depending on the region.</p>


View a detailed weather forecast for Illinois for the next 7, 10 and 14 days, giving you a look further ahead including sun, rain, wind &amp; humidity forecast.


Illinois 7, 10 & 14 Day Weather Forecast | Thomas Cook

<p>Check out the Illinois&nbsp;weather forecast for the next two weeks. Planning a trip to Illinois&nbsp;in the near future? For a glimpse of the daily weather, take a look at our 14-day guide which offers you all the details you need to know. We want to help with the prep work before you go, so all you need to focus on is enjoying your holiday. To get an idea of whether it will be chilly or sunny in the next two weeks, use our weather forecast below. You can use it to decide when to explore the region, and when to plan any indoor activities. It&rsquo;s also useful as a packing guide for your upcoming trip.</p>


Are you travelling to Illinois&nbsp;and want to know what the weather will be like? Check out the best times to visit.


Illinois Weather | Thomas Cook

Going to Illinois in September and want to know what the weather will be like? Visit our holiday weather guide and be prepared for your holiday.

Illinois Weather in September

Illinois Weather September

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