Average annual temperature is 5.9 °C
Absolute maximum temperature: 34.7 °C
Absolute minimum temperature: -30.6 °C
Number of sunny days: 213 days
Number of rainy days: 105 days
Number of snow days: 47 days
Look at detailed online map of McHenry County
* Weather data for McHenry 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) | 2.5 | 4.3 | 1.3 | 14.5 | 28.6 | 34.3 | 33.7 | 34.7 | 33.2 | 28.1 | 11.5 | 9.7 |
| Average daytime temperature (°C) | -5.9 | -3.7 | -5.0 | 5.7 | 22.7 | 27.3 | 26.9 | 27.4 | 23.9 | 11.6 | 4.1 | 1.9 |
| Average temperature (°C) | -9.9 | -9.1 | -9.9 | 0.7 | 15.4 | 21.3 | 20.3 | 21.0 | 17.3 | 6.4 | -0.4 | -2.8 |
| Average night temperature (°C) | -13.2 | -13.7 | -13.5 | -3.4 | 8.9 | 15.3 | 14.6 | 15.9 | 11.9 | 2.4 | -3.8 | -6.2 |
| Absolute minimum temperature (°C) | -26.8 | -30.6 | -21.5 | -13.7 | -2.8 | 8.5 | 9.3 | 11.5 | 6.9 | -16.9 | -13.4 | -12.1 |
| 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 | 16.0 | 16.0 | 15.0 | 13.0 | 11.0 | 9.0 | 8.0 |
| Daylight mean duration (h) | 8.9 | 10.2 | 11.9 | 13.7 | 15.2 | 16.0 | 15.6 | 14.3 | 12.6 | 10.8 | 9.3 | 8.4 |
| Daylight minimum duration (h) | 8.0 | 9.0 | 11.0 | 12.0 | 14.0 | 15.0 | 15.0 | 13.0 | 11.0 | 9.0 | 8.0 | 8.0 |
| Sunshine mean duration (h) | 3.7 | 7.0 | 8.0 | 9.0 | 11.4 | 12.3 | 13.2 | 10.4 | 9.5 | 7.1 | 6.0 | 5.8 |
| Precipitation (mm) | 6 | 9 | 30 | 51 | 76 | 68 | 24 | 54 | 26 | 68 | 5 | 16 |
| Sunny days | 23 | 16 | 16 | 15 | 16 | 15 | 16 | 15 | 19 | 15 | 21 | 26 |
| Rainy days | 1 | 3 | 0 | 10 | 15 | 15 | 15 | 16 | 11 | 13 | 5 | 1 |
| Snow days | 7 | 9 | 15 | 5 | 0 | 0 | 0 | 0 | 0 | 3 | 4 | 4 |
The best time to visit McHenry County during the most sunny months:
Months with the longest average daylight duration in McHenry County:
The largest precipitation sum in McHenry County is at