Chicago Climate — Average Highs, Lows & Rainfall by Month
Chicago has a temperate climate with four distinct seasons. Daytime temperatures average 27°C / 81°F in July, the warmest month, and drop to 0°C / 32°F in January, the coldest. Overnight lows in January average -7°C / 19°F. Chicago receives about 1074 mm of rain a year across roughly 119 wet days, with July the wettest month.
Averages for 2021–2025 · Open-Meteo Historical Weather API (ERA5 reanalysis) · Updated 2026-10-05
Monthly averages in Chicago
Average daytime high, overnight low and rainfall for each month of the year.
| Month | Avg high | Avg low | Rainfall | Wet days |
|---|---|---|---|---|
| January | 0°C / 32°F | -7°C / 19°F | 68 mm | 10 |
| February | 2°C / 36°F | -6°C / 21°F | 52 mm | 7 |
| March | 9°C / 48°F | 0°C / 33°F | 97 mm | 12 |
| April | 14°C / 57°F | 5°C / 41°F | 83 mm | 13 |
| May | 19°C / 67°F | 11°C / 51°F | 91 mm | 11 |
| June | 27°C / 80°F | 17°C / 63°F | 102 mm | 9 |
| July | 27°C / 81°F | 19°C / 67°F | 164 mm | 12 |
| August | 27°C / 80°F | 19°C / 66°F | 102 mm | 10 |
| September | 24°C / 75°F | 16°C / 61°F | 83 mm | 7 |
| October | 18°C / 64°F | 10°C / 50°F | 111 mm | 11 |
| November | 10°C / 49°F | 2°C / 36°F | 55 mm | 7 |
| December | 4°C / 39°F | -3°C / 27°F | 67 mm | 10 |
Best time to visit Chicago
September, May, June offer the most comfortable weather in Chicago: mild daytime temperatures with the year's lowest rainfall — September averages 24°C (75°F); May averages 19°C (67°F); June averages 27°C (80°F).
Chicago climate FAQ
- What is the hottest month in Chicago?
- July is the hottest month in Chicago, with average daytime highs of 27°C / 81°F and overnight lows of 19°C / 67°F (averages for 2021–2025).
- What is the coldest month in Chicago?
- January is the coldest month in Chicago, with average highs of 0°C / 32°F and lows of -7°C / 19°F.
- How much rain does Chicago get a year?
- Chicago receives about 1074 mm of rainfall a year, spread over roughly 119 wet days. July is the wettest month (164 mm on average) and February the driest (52 mm).
- When is the best time to visit Chicago?
- September, May, June are the most comfortable months in Chicago: mild daytime temperatures with the least rainfall of the year.
Want today's conditions instead of averages?
See live weather in Chicago →Source: Open-Meteo Historical Weather API (ERA5 reanalysis), Open-Meteo. Averages are daily means across 2021–2025 and are rounded for display — for a live forecast see the Chicago weather page.