Chicago, Illinois weather in December

Averages from 2021–2025 (155 days of record).

Average high: 39°F
Average low: 27°F
Rainy days: ~10 per month
Total precipitation: 2.6 in
Warmest recorded: 64°F
Coldest recorded: -10°F

Expect December days in Chicago, Illinois to top out around 39°F and cool to about 27°F overnight, with roughly 10 days of measurable rain across the month. In recent years December has ranged from -10°F to 64°F.

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Current Chicago, Illinois forecast → · Historical data by Open-Meteo (ERA5).