Napa Weather in August

What's the weather like in Napa (California) in August 2025?

The climate in Napa during August can be summarized as warm and very dry.

August is in the summer in Napa and is typically the warmest month of the year. Daytime maximum temperatures average around a comfortable 28°C (82°F), whilst at night 12°C (54°F) is normal.

Napa weather averages (imperial / metric)
Daytime temperature 27.9°C 82.2°F
Nightly temperature 12.1°C 53.8°F
Average temperature 20°C 68°F
Daily sunshine 11.5 hrs
Avg rainfall 3 mm 0.1 ins
Rainy days 1 days
Sea temperature 14°C 57.2°F
Humidity 66%
Windspeed 16.9kph 11 mph

On average August is the 2nd driest month of the year in Napa with around 3mm 0.1 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 11.5 hours of sunshine per day.

August temperatures in Napa

Napa average temperature in August

August rainfall

Napa average rain in August

August hourly sunshine

Napa average rain in August

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Napa in August 2025.

Other monthly averages

Best places to visit in August

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Napa weather stats

Napa weather statistics
Hottest month: July 27.7°C 81.9°F
Driest month: July 1mm 0ins
Sunniest month: May 12.2hrs
Coldest month: January 12.6°C 54.7°F
Wettest month: January 157mm 6.2ins
Map showing location of Napa (38.29714, -122.28553) Napa map pin © Google

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