Napa Climate by Month
Napa, California, United States
Hot summers and cool winters, with most rain from December to March.
The climate in Napa is one of hot summers and cool winters, with most rain from December to March. Afternoon highs range from 58°F (14°C) in January to 87°F (31°C) in August, and December nights average 38°F (4°C). Of the 26 in (669 mm) of rain in a typical year, 74% falls from December to March. June to September are almost completely dry.
- Warmest month
- 87°F(31°C)
- Average high, August
- Coldest nights
- 38°F(4°C)
- Average low, December
- Rain per year
- 26 in(669 mm)
- Wettest: January
- Humidity
- 64%
- Sunniest: July
Best and worst months in Napa
Best for weatherApril, May and October are the best time for weather in Napa: highs near 76°F (25°C) and about 1.3 in (33 mm) of rain a month.
Least pleasantDecember and January are the least pleasant; January is the coldest, with highs of only 58°F (14°C).
Comfort combines how close the afternoon high is to 75°F (24°C) with how much rain falls and how humid it is. See where the weather is best in May.
Temperature and rain through the year
Highs and lows (°F)
Average highAverage low
Rain (in per month)
Napa weather by month
| Month | High | Low | Rain | Humidity | Sun |
|---|---|---|---|---|---|
| JanJanuary | 58°F(14°C) | 39°F(4°C) | 5.4 in(136 mm) | 78% | 1.8 |
| FebFebruary | 63°F(17°C) | 41°F(5°C) | 5.3 in(134 mm) | 76% | 2.6 |
| MarMarch | 67°F(19°C) | 43°F(6°C) | 3.6 in(92 mm) | 67% | 4.2 |
| AprAprilBest | 72°F(22°C) | 45°F(7°C) | 1.6 in(40 mm) | 65% | 5.4 |
| MayMayBest | 78°F(25°C) | 49°F(10°C) | 1.0 in(25 mm) | 60% | 6.3 |
| JunJune | 84°F(29°C) | 53°F(12°C) | 0.2 in(6 mm) | 54% | 7.4 |
| JulJuly | 87°F(30°C) | 54°F(12°C) | 0.0 in(0 mm) | 55% | 7.4 |
| AugAugust | 87°F(31°C) | 54°F(12°C) | 0.0 in(1 mm) | 55% | 6.6 |
| SepSeptember | 86°F(30°C) | 52°F(11°C) | 0.1 in(3 mm) | 53% | 5.5 |
| OctOctoberBest | 79°F(26°C) | 48°F(9°C) | 1.3 in(33 mm) | 55% | 3.8 |
| NovNovember | 67°F(19°C) | 42°F(6°C) | 2.7 in(69 mm) | 70% | 2.5 |
| DecDecember | 58°F(15°C) | 38°F(4°C) | 5.1 in(130 mm) | 78% | 1.6 |
1991–2020 averages. Sun is solar radiation in kWh/m² per day. Highlighted: the most comfortable months.
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