Illinois (Chicago)
December
Weather in Illinois for December 2025
Your guide to Illinois weather in December - trends and predictions
With an average of 5 snowy days, Illinois usually enjoys a light touch of snow in December.
In general, the average temperature in Illinois at the beginning of December is 5 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 4 °F by the end of December.
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Snow Forecast ❄️
Temperatures
More
11
Dry days
15
Rainy days
5
Snow days
4°/-1°
Temperatures
24 km/h
Avg max wind
71 %
Avg humidity
Illinois in December average weather
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| Sun. | Mon. | Tue. | Wed. | Thu. | Fri. | Sat. |
|---|---|---|---|---|---|---|
| 1  5° | 2  6° | 3  6° | 4 4° | 5  4° | 6 4° | |
| 7 6° | 8 5° | 9 7° | 10  7° | 11 5° | 12 3° | 13  4° |
| 14 6° | 15 7° | 16 6° | 17 3° | 18 2° | 19 1° | 20 3° |
| 21 3° | 22 3° | 23 2° | 24 2° | 25 2° | 26 3° | 27 5° |
| 28 5° | 29 5° | 30 5° | 31 3° |
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Temperatures trend during December in Illinois
See the weather trend as well as the moving average line
December weather day by day
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| Date | Weather | Temperatures | Rain | Snow | More |
|---|---|---|---|---|---|
| Dec. 1 | Overcast | 5° /-2° | 3.8 mm | 0 cm | |
| Dec. 2 | Patchy rain possible | 6° /1° | 1 mm | 0 cm | |
| Dec. 3 | Partly cloudy | 6° /0° | 4.2 mm | 0 cm | |
| Dec. 4 | Overcast | 4° /-1° | 0 mm | 0 cm | |
| Dec. 5 | Moderate or heavy rain shower | 4° /-2° | 4.6 mm | 0.4 cm | |
| Dec. 6 | Overcast | 4° /-3° | 0 mm | 0 cm | |
| Dec. 7 | Overcast | 6° /-1° | 0 mm | 0 cm | |
| Dec. 8 | Overcast | 5° /1° | 0.1 mm | 0 cm | |
| Dec. 9 | Patchy rain possible | 7° /2° | 3.7 mm | 0 cm | |
| Dec. 10 | Sunny | 7° /1° | 3.4 mm | 0 cm | |
| Dec. 11 | Moderate rain at times | 5° /0° | 3 mm | 0 cm | |
| Dec. 12 | Partly cloudy | 3° /-2° | 8.4 mm | 0 cm | |
| Dec. 13 | Cloudy | 4° /-1° | 0.1 mm | 0 cm | |
| Dec. 14 | Overcast | 6° /0° | 6.9 mm | 0 cm | |
| Dec. 15 | Patchy rain possible | 7° /2° | 5.3 mm | 0 cm | |
| Dec. 16 | Overcast | 6° /1° | 2.7 mm | 0 cm | |
| Dec. 17 | Overcast | 3° /0° | 0.3 mm | 0 cm | |
| Dec. 18 | Overcast | 2° /-2° | 2.1 mm | 0.4 cm | |
| Dec. 19 | Overcast | 1° /-3° | 0 mm | 0 cm | |
| Dec. 20 | Overcast | 3° /-1° | 0 mm | 0 cm | |
| Dec. 21 | Patchy rain possible | 3° /-1° | 0.3 mm | 0 cm | |
| Dec. 22 | Overcast | 3° /-3° | 3.6 mm | 0.6 cm | |
| Dec. 23 | Overcast | 2° /-3° | 1.4 mm | 0 cm | |
| Dec. 24 | Overcast | 2° /-4° | 0.2 mm | 0 cm | |
| Dec. 25 | Cloudy | 2° /-3° | 2.1 mm | 0 cm | |
| Dec. 26 | Sunny | 3° /-3° | 0.6 mm | 0 cm | |
| Dec. 27 | Overcast | 5° /0° | 4.3 mm | 0 cm | |
| Dec. 28 | Overcast | 5° /1° | 2.8 mm | 0 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.
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 72 mm spread over approximately 15 days. Considering plans for rainy days is advisable.
Will it snow in Illinois in December 2025?
Illinois experiences an average snowfall of 4.222 cm during December, occurring over 5 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
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December rainfall patterns in Illinois
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