Napa weather in August
August in Napa: hot, dry, with clean air — an excellent time to visit.
#7 of 12 months in Napa · #197 of 604 destinations to visit in August · comfort 85/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Napa climate normals — August
| Daytime high | 33°C / 91°F | 🥵 hot |
|---|---|---|
| Nighttime low | 16°C / 61°F | |
| Feels like (high) | 33°C / 91°F | |
| Rainfall | 0 mm / 0 in | ☀️ dry |
| Rainy days | 0 days | |
| Humidity | 59% | 🍃 comfortable |
| Dew point | 13°C / 56°F | |
| Sunshine | 12.4 h/day | |
| Daylight | 13.6 h | |
| Wind | 16 km/h / 10 mph | |
| Air quality (US AQI) | 34 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Napa in August — FAQ
- Is August a good time to visit Napa?
- August in Napa: hot, dry, with clean air — an excellent time to visit. It ranks #7 of 12 months for Napa on SeasonMap's comfort score (85/100).
- What is the weather like in Napa in August?
- In August, Napa averages a daily high of 32.9°C and a low of 15.9°C, with about 0.2 mm of rain over roughly 0 rainy days.
- What is the air quality in Napa in August?
- Napa has a mean US Air Quality Index of about 34 in August.