Weather Calendar December 2024 Chicago Illinois. Get the monthly weather forecast for chicago, il, including daily high/low, historical averages, to help you plan ahead. Is this the best time to travel?

Insights into temperature, precipitation, and weather trends. A shift in chicago’s weather is observed as november turns into december, with the average high temperature reducing from a frosty 46°f (7.8°c) to a cold 35.8°f (2.1°c).