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The weather in Illinois in January is very cold with temperatures between -7°C and -2°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Illinois during the month of January. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Let it snow! You can expect Illinois to be covered in white during the month of January. Be sure to bundle up when you venture outside, or take the opportunity to enjoy hot cocoa by the fire for warmth this month.
Our weather forecast can give you a great sense of what weather to expect in Illinois in January 2025.
If you’re planning to visit Illinois in the near future, we highly recommend that you review the 14 day weather forecast for Illinois before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -2° / -7° | 5 | 11 | 15 | 39 mm | Awful | Illinois in January |
| February | 0° / -6° | 4 | 11 | 14 | 41 mm | Awful | Illinois in February |
| March | 7° / 1° | 6 | 19 | 6 | 55 mm | Bad | Illinois in March |
| April | 12° / 5° | 7 | 21 | 3 | 79 mm | Awful | Illinois in April |
| May | 19° / 12° | 7 | 24 | 0 | 98 mm | Ok | Illinois in May |
| June | 24° / 17° | 7 | 23 | 0 | 128 mm | Good | Illinois in June |
| July | 27° / 20° | 7 | 24 | 0 | 114 mm | Good | Illinois in July |
| August | 27° / 19° | 5 | 26 | 0 | 100 mm | Perfect | Illinois in August |
| September | 24° / 16° | 4 | 26 | 0 | 64 mm | Perfect | Illinois in September |
| October | 16° / 10° | 5 | 25 | 0 | 65 mm | Good | Illinois in October |
| November | 9° / 3° | 4 | 22 | 4 | 40 mm | Bad | Illinois in November |
| December | 3° / -2° | 5 | 16 | 10 | 38 mm | Awful | Illinois in December |