Illinois (Chicago)
December
Weather in Illinois for December 2025
Your guide to Illinois weather in December - trends and predictions
Illinois typically experiences moderate snowfall in December, with an average of 6 snowy days.
According to Illinois snow forecast for December 2025, 7 snowy days are expected until the end of the month. The closest date with snow is Thursday, December 18.Until now, December 2025 in Illinois is cooler than usual, with temperatures averaging -0.5 °F, this is -4.6 °F below the typical seasonal average.
The forecast for the next days in Illinois predicts a temperature of -0.3 °F, which is cooler than the historical average.
In general, the average temperature in Illinois at the beginning of December is 3.9 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 0 °F by the end of December.
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Snow Forecast ❄️
Temperatures
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11
Dry days
14
Rainy days
6
Snow days
4°/0°
Temperatures
24 km/h
Avg max wind
73 %
Avg humidity
Illinois Weather December
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What’s the Weather Like in Illinois This December?
Discover the average temperatures and weather trends across Illinois’s cities this December.
Temperatures trend during December in Illinois
See the weather trend as well as the moving average line
December weather in Illinois day by day
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| Date | Weather | Temperatures | Rain | Snow | More |
|---|---|---|---|---|---|
| Dec. 1 |  Overcast | 4° /-2° | 5.3 mm | 1.6 cm | |
| Dec. 2 |  Patchy rain possible | 5° /0° | 1 mm | 0.2 cm | |
| Dec. 3 |  Partly cloudy | 5° /-1° | 4.8 mm | 0.8 cm | |
| Dec. 4 | Overcast | 2° /-3° | 0 mm | 0 cm | |
| Dec. 5 | Overcast | 3° /-4° | 3.7 mm | 0.3 cm | |
| Dec. 6 | Overcast | 3° /-3° | 0 mm | 0 cm | |
| Dec. 7 | Overcast | 5° /-1° | 1.4 mm | 1 cm | |
| Dec. 8 | Overcast | 4° /0° | 0.1 mm | 0 cm | |
| Dec. 9 | Overcast | 6° /1° | 3 mm | 0 cm | |
| Dec. 10 | Overcast | 6° /1° | 4.2 mm | 0 cm | |
| Dec. 11 | Overcast | 4° /-1° | 2.5 mm | 0 cm | |
| Dec. 12 | Partly cloudy | 3° /-2° | 8 mm | 0.7 cm | |
| Dec. 13 |  Cloudy | 3° /-3° | 1.5 mm | 1 cm | |
| Dec. 14 | Partly cloudy | 4° /-2° | 5.7 mm | 0 cm | |
| Dec. 15 |  Sunny | -4° /-17° | 0 mm | 0 cm | |
| Dec. 16 | Overcast | 4° /-8° | 0 mm | 0 cm | |
| Dec. 17 | Overcast | -1° /-2° | 0 mm | 0 cm | |
| Dec. 18 |  Moderate rain | 9° /-5° | 12.6 mm | 0.8 cm | |
| Dec. 19 | Overcast | -6° /-10° | 0 mm | 0 cm | |
| Dec. 20 |  Moderate or heavy snow showers | 3° /-3° | 1.6 mm | 1.2 cm | |
| Dec. 21 |  Light freezing rain | -3° /-8° | 0.2 mm | 0.1 cm | |
| Dec. 22 | Sunny | 1° /-8° | 0 mm | 0 cm | |
| Dec. 23 | Partly cloudy | 5° /2° | 0 mm | 0 cm | |
| Dec. 24 | Sunny | 1° /-4° | 0 mm | 0 cm | |
| Dec. 25 | Light freezing rain | -1° /-6° | 0.2 mm | 0.1 cm | |
| Dec. 26 |  Blowing snow | -2° /-9° | 0.5 mm | 0.3 cm | |
| Dec. 27 | Partly cloudy | -8° /-11° | 0 mm | 0 cm | |
| Dec. 28 | Light freezing rain | -2° /-8° | 0.2 mm | 0.1 cm | |
| Dec. 29 | Overcast | 5° /1° | 2.6 mm | 1.2 cm | |
| Dec. 30 | Overcast | 5° /0° | 2.8 mm | 1.2 cm | |
| Dec. 31 | Overcast | 3° /-2° | 9.9 mm | 3.9 cm | |
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Important Notice
Our weather forecast for Illinois in December is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Illinois forecast closer to your planned date for the most up-to-date weather information.
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Illinois in December - FAQ
What are the expected maximum and minimum temperatures in Illinois during December?
Brace for cold days with temperatures not exceeding 4° and nights that are likely to be freezing. Winter clothing is essential for comfort and safety.
How much rainfall should be expected in Illinois during December?
Moderate rainfall is anticipated in Illinois during December, with a total of 80.2 mm spread over approximately 14 days. Considering plans for rainy days is advisable.
Will it snow in Illinois in December 2025?
Illinois experiences an average snowfall of 7.601 cm during December, occurring over 6 days.
What are the typical wind conditions in Illinois during December?
The average wind speed in Illinois during December is 24 km/h, suggesting breezy to windy conditions, depending on your activities.
Illinois snow forecast December 2025
Track daily snowfall levels and discover Illinois’s snowy potential this December ❄️
On average, Illinois sees 6 snowy days during December, with approximately 7.6 cm of total snowfall.
December rainfall patterns in Illinois
Explore the daily rainfall trends and prepare for Illinoiss December weather 💧
Typically, Illinois has 14 rainy days in December with a total of 80.2 mm of rainfall.
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