Napa weather in December
December in Napa: cool, rainy, with clean air — a good time to visit.
#12 of 12 months in Napa · #333 of 604 destinations to visit in December · comfort 68/100 (tier C)
Updated June 2026 · climate normals from ERA5 reanalysis
Napa climate normals — December
| Daytime high | 15°C / 59°F | 🙂 cool |
|---|---|---|
| Nighttime low | 7°C / 44°F | |
| Feels like (high) | 13°C / 55°F | |
| Rainfall | 136 mm / 5.4 in | 🌧 rainy |
| Rainy days | 12 days | |
| Humidity | 83% | 💦 very humid |
| Dew point | 7°C / 44°F | |
| Sunshine | 5.9 h/day | |
| Daylight | 9.5 h | |
| Wind | 12 km/h / 7 mph | |
| Air quality (US AQI) | 35 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Napa in December — FAQ
- Is December a good time to visit Napa?
- December in Napa: cool, rainy, with clean air — a good time to visit. It ranks #12 of 12 months for Napa on SeasonMap's comfort score (68/100).
- What is the weather like in Napa in December?
- In December, Napa averages a daily high of 15°C and a low of 6.5°C, with about 136.2 mm of rain over roughly 12 rainy days.
- What is the air quality in Napa in December?
- Napa has a mean US Air Quality Index of about 35 in December.