Average annual temperature is 10.5 °C
Absolute maximum temperature: 37.7 °C
Absolute minimum temperature: -21.4 °C
Number of sunny days: 229 days
Number of rainy days: 118 days
Number of snow days: 18 days
Look at detailed online map of Romeroville
* Weather data for Romeroville 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) | 15.1 | 14.4 | 16.9 | 24.8 | 26.9 | 32.6 | 37.7 | 33.4 | 31.4 | 27.3 | 22.2 | 15.5 |
| Average daytime temperature (°C) | 6.3 | 8.2 | 10.8 | 18.5 | 22.4 | 26.2 | 32.6 | 29.5 | 26.0 | 20.3 | 13.5 | 7.0 |
| Average temperature (°C) | 0.1 | 0.5 | 3.9 | 9.5 | 14.3 | 18.1 | 23.6 | 21.6 | 17.8 | 11.4 | 5.2 | -0.8 |
| Average night temperature (°C) | -4.8 | -5.2 | -1.9 | 1.4 | 6.6 | 9.4 | 14.2 | 13.8 | 9.8 | 3.8 | -1.2 | -6.7 |
| Absolute minimum temperature (°C) | -19.3 | -21.4 | -15.3 | -5.8 | 2.3 | 3.4 | 10.2 | 9.6 | 3.9 | -6.6 | -8.7 | -17.3 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight maximum duration (h) | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 14.0 | 13.0 | 12.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 10.1 | 10.9 | 12.0 | 13.1 | 14.0 | 14.5 | 14.3 | 13.5 | 12.4 | 11.3 | 10.3 | 9.8 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 13.0 | 12.0 | 11.0 | 10.0 | 9.0 | 9.0 |
| Sunshine mean duration (h) | 8.0 | 8.8 | 10.0 | 11.7 | 11.3 | 12.6 | 12.9 | 11.6 | 11.1 | 9.9 | 8.2 | 7.9 |
| Precipitation (mm) | 16 | 26 | 32 | 4 | 84 | 41 | 21 | 29 | 19 | 8 | 5 | 39 |
| Sunny days | 21 | 19 | 15 | 25 | 10 | 15 | 16 | 13 | 20 | 25 | 25 | 25 |
| Rainy days | 3 | 4 | 12 | 5 | 21 | 15 | 15 | 18 | 10 | 6 | 4 | 5 |
| Snow days | 7 | 5 | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
The largest precipitation sum in Romeroville is at