Napa (CA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Napa.
Climate overview of Napa
Temperatures in Napa, California, United States of America, vary greatly throughout the year. September is the hottest month at 30°C (86°F), while December is the coldest at 14°C (57°F).
Napa sees a moderate amount of rainfall, totalling around 585 mm (23 in) per year. It experiences a distinct dry season from May to October, with warm summers and mild winters, creating some seasonal variation. The sunniest month is May, with 10.3 hours of sunshine per day on average.
Napa Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Napa - and find the best time to visit.
Monthly Temperature in Napa
The climate in Napa is known for significant temperature differences throughout the year, making the weather dynamic. Average maximum daytime temperatures range from a comfortable 30°C (86°F) in September, the warmest time of the year, to a moderate 14°C (57°F) during cooler months like December.
At night, you can expect temperatures ranging from 13°C (55°F) in September to around 4°C (39°F) during December.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Napa
Generally, Napa receives mid-range precipitation levels, with 585 mm (23 in) annually. Significant seasonal changes in precipitation occur throughout the year. In the wettest month, December it receives high rainfall, averaging 120 mm (4.7 in) of precipitation, recorded across 11 rainy days. In contrast, the driest month July brings less rainfall, with 0.1 mm (0 in) over 0 rainy days. For more details, please visit our Napa Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Napa
Seasonal changes in sunshine hours are quite dramatic in Napa. While May receives considerable daily sunshine with up to 10.3 hours, December marks the darkest time of the year, where sunshine is scarce with only 5.3 hours of sunlight per day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Best Time to Visit Napa
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: April, May, June, July, August and October
- Warmest weather: June, July, August and September
- Most sunshine: April, May, June and July
- Fewest rainy days: June, July, August and September
- Wettest months: January, February, March, April, November and December, when rainfall is highest.
- Seasonal pattern: a distinct dry season from May to October, with warm summers and mild winters
Frequently asked questions about the climate in Napa
What is the best time to visit Napa?
April, May, June, July, August and October typically offer the most optimal weather in Napa. In contrast, February and December tend to have less optimal conditions. Napa has a distinct dry season from May to October, with warm summers and mild winters.
What temperatures can I expect in Napa?
Daytime highs range from 14°C (57°F) in December to 30°C (86°F) in September. Nighttime lows range from 4°C (39°F) to 13°C (55°F). Temperatures vary considerably through the year.
How much rain does Napa get?
Annual rainfall is around 585 mm (23 in). December is the wettest month with 120 mm (4.7 in), while July is the driest with 0.1 mm (0 in).
How sunny is Napa?
Napa receives around 3,042 hours of sunshine per year. May is the sunniest month with 310 hours, while December is the cloudiest with just 160 hours. Overall, Napa enjoys abundant sunshine.
Napa 3-Day Forecast
Napa (CA) 3-Day Forecast
Napa on the map
Napa is highlighted - select any city to see its climate.
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