Weather information for the Napa Valley area is provided below. Average temperatures, climate details and current forecasts are included.
Close to the ocean and yet shielded by mountains, Napa Valley has a wet but temperate climate ideal for both vineyards and visitors. The bulk of the year features long, warm days with little moisture, followed by cool evenings. During winter there is more moisture, but temperatures never become extreme in either direction.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | ||
| Avg. High | 57 | 62 | 65 | 71 | 75 | 81 | 83 | 82 | 82 | 76 | 64 | 57 | |
| Avg. Low | 39 | 42 | 43 | 45 | 49 | 53 | 55 | 55 | 53 | 49 | 43 | 39 | |
| Precipitation | 5.4 | 5.0 | 4.1 | 1.5 | 0.8 | 0.2 | 0.1 | 0.1 | 0.4 | 1.4 | 3.7 | 3.9 | |
