Average annual temperature is 14.6 °C
Absolute maximum temperature: 41.5 °C
Absolute minimum temperature: -1.6 °C
Number of sunny days: 261 days
Number of rainy days: 104 days
Look at detailed online map of Napa County
* Weather data for Napa 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) | 18.5 | 22.1 | 18.3 | 32.3 | 34.1 | 37.6 | 41.5 | 40.0 | 33.6 | 34.2 | 25.8 | 19.3 |
| Average daytime temperature (°C) | 13.4 | 14.1 | 13.2 | 21.3 | 23.7 | 27.2 | 34.9 | 34.2 | 28.3 | 26.1 | 18.5 | 15.3 |
| Average temperature (°C) | 8.3 | 7.0 | 7.5 | 12.8 | 15.5 | 18.1 | 23.8 | 23.5 | 19.1 | 17.1 | 11.8 | 9.6 |
| Average night temperature (°C) | 5.2 | 2.4 | 3.5 | 6.3 | 9.5 | 11.2 | 14.5 | 15.6 | 12.8 | 11.2 | 7.2 | 6.0 |
| Absolute minimum temperature (°C) | -0.7 | -1.1 | -1.6 | 0.9 | 5.0 | 9.0 | 9.6 | 12.2 | 9.8 | 4.4 | 2.3 | 2.0 |
| 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 | 14.0 | 13.0 | 11.0 | 10.0 | 9.0 |
| Daylight mean duration (h) | 9.8 | 10.8 | 12.0 | 13.2 | 14.3 | 14.8 | 14.5 | 13.6 | 12.4 | 11.2 | 10.1 | 9.5 |
| 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) | 5.4 | 7.7 | 7.2 | 11.3 | 11.7 | 13.0 | 13.4 | 12.3 | 11.0 | 9.1 | 7.7 | 5.4 |
| Precipitation (mm) | 324 | 105 | 306 | 13 | 31 | 0 | 0 | 1 | 7 | 31 | 52 | 149 |
| Sunny days | 13 | 16 | 10 | 25 | 25 | 29 | 30 | 29 | 24 | 24 | 22 | 14 |
| Rainy days | 18 | 12 | 21 | 5 | 6 | 1 | 1 | 2 | 6 | 7 | 8 | 17 |
| Snow days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
The best time to visit Napa County during the most sunny months:
The largest precipitation sum in Napa County is at