Average annual temperature is 12.8 °C
Absolute maximum temperature: 34.6 °C
Absolute minimum temperature: -10.6 °C
Number of sunny days: 178 days
Number of rainy days: 182 days
Number of snow days: 5 days
Look at detailed online map of Cornwall
* Weather data for Cornwall 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) | 16.8 | 18.9 | 20.1 | 29.6 | 30.5 | 33.8 | 34.6 | 31.7 | 34.2 | 27.8 | 21.5 | 16.2 |
| Average daytime temperature (°C) | 8.1 | 9.8 | 10.6 | 19.5 | 22.7 | 26.4 | 30.3 | 28.3 | 24.4 | 19.3 | 11.3 | 8.7 |
| Average temperature (°C) | 4.2 | 4.0 | 4.9 | 13.0 | 15.6 | 20.0 | 24.5 | 22.9 | 19.3 | 14.1 | 6.0 | 4.6 |
| Average night temperature (°C) | 1.0 | -0.9 | 0.0 | 7.2 | 8.6 | 14.2 | 19.4 | 18.2 | 15.0 | 9.8 | 1.8 | 1.3 |
| Absolute minimum temperature (°C) | -4.8 | -10.6 | -6.1 | -1.1 | 2.5 | 8.1 | 15.6 | 14.3 | 9.4 | 2.9 | -5.6 | -4.1 |
| 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 | 15.0 | 15.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 9.7 | 10.7 | 11.9 | 13.3 | 14.4 | 15.0 | 14.7 | 13.7 | 12.5 | 11.1 | 10.0 | 9.4 |
| Daylight minimum duration (h) | 9.0 | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 | 9.0 |
| Sunshine mean duration (h) | 4.8 | 6.8 | 7.4 | 9.1 | 11.4 | 10.8 | 12.1 | 10.5 | 8.1 | 8.0 | 7.5 | 4.1 |
| Precipitation (mm) | 85 | 37 | 73 | 130 | 16 | 108 | 105 | 154 | 119 | 75 | 64 | 120 |
| Sunny days | 12 | 17 | 12 | 16 | 21 | 12 | 6 | 14 | 16 | 20 | 19 | 13 |
| Rainy days | 19 | 9 | 18 | 14 | 10 | 18 | 25 | 17 | 14 | 11 | 11 | 16 |
| Snow days | 0 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
The best time to visit Cornwall during the most sunny months:
The largest precipitation sum in Cornwall is at