Average annual temperature is 3.7 °C
Absolute maximum temperature: 23.6 °C
Absolute minimum temperature: -25.1 °C
Number of sunny days: 188 days
Number of rainy days: 129 days
Number of snow days: 48 days
Look at detailed online map of Cook County
* Weather data for Cook County United States is based on climate observations for 2026 year
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Absolute maximum temperature (°C) | 1.0 | 3.0 | 1.8 | 12.0 | 14.0 | 20.6 | 21.4 | 22.3 | 23.6 | 19.9 | 10.7 | 5.1 |
| Average daytime temperature (°C) | -3.8 | -4.1 | -1.6 | 1.9 | 7.4 | 11.2 | 15.0 | 17.2 | 15.9 | 9.7 | 3.5 | 1.4 |
| Average temperature (°C) | -5.9 | -7.4 | -3.9 | -0.4 | 4.6 | 7.4 | 11.3 | 14.9 | 14.3 | 8.0 | 0.9 | -0.5 |
| Average night temperature (°C) | -7.6 | -10.2 | -5.8 | -2.2 | 2.5 | 4.9 | 8.7 | 13.6 | 13.1 | 6.7 | -1.1 | -1.8 |
| Absolute minimum temperature (°C) | -21.8 | -25.1 | -11.0 | -7.3 | -3.1 | 2.3 | 6.1 | 11.6 | 9.5 | -3.9 | -11.9 | -9.3 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 9.0 | 10.0 | 12.0 | 14.0 | 15.0 | 15.0 | 15.0 | 14.0 | 13.0 | 11.0 | 9.0 | 8.0 |
| Daylight mean duration (h) | 8.9 | 10.3 | 11.9 | 13.6 | 15.1 | 15.9 | 15.5 | 14.2 | 12.6 | 10.9 | 9.3 | 8.5 |
| Daylight minimum duration (h) | 8.0 | 9.0 | 11.0 | 12.0 | 14.0 | 15.0 | 15.0 | 13.0 | 11.0 | 10.0 | 8.0 | 8.0 |
| Sunshine mean duration (h) | 3.2 | 6.7 | 7.4 | 7.2 | 11.6 | 12.0 | 12.4 | 10.6 | 8.5 | 5.7 | 5.0 | 3.3 |
| Precipitation (mm) | 31 | 49 | 43 | 119 | 14 | 59 | 51 | 74 | 54 | 48 | 43 | 53 |
| Sunny days | 18 | 14 | 15 | 13 | 22 | 19 | 15 | 17 | 12 | 11 | 17 | 15 |
| Rainy days | 4 | 3 | 2 | 12 | 9 | 11 | 16 | 14 | 18 | 18 | 10 | 12 |
| Snow days | 9 | 11 | 14 | 5 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 4 |
The best time to visit Cook County during the most sunny months:
Months with the longest average daylight duration in Cook County:
The largest precipitation sum in Cook County is at