Temperature in The Napa Valley in September

Daytime highs, nighttime lows and the warmest cities in the Napa Valley, the United States of America this September.

The Napa Valley, the United States of America, a region in the United States of America, experiences maximum daytime temperatures in September ranging from 28°C (82°F) in American Canyon to 31°C (88°F) in Calistoga. Nighttime temperatures generally drop to 11°C (52°F) in Calistoga and 11°C (52°F) in American Canyon. September falls during the summer season. In the Napa Valley, the United States of America, September typically stands out as the hottest month of the year. If you're planning a visit during this time, it would be wise to come prepared. Packing light and breathable summer cloths will ensure you stay comfortable throughout your stay.

What is the temperature of the different cities in the Napa Valley, the United States of America in September?

Curious about the September temperatures in the prime spots of the Napa Valley? Navigate the map below and tap on a destination dot for more detailed stats.

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Check the conditions for any month of the year.

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For a detailed overview over the year and the best time to visit the Napa Valley, check out our the Napa Valley's climate page.

See also: the Napa Valley weather by month.

Best Places to Visit in the Napa Valley in September

Click on a destination dot for more details. Toggle the map to compare temperatures or precipitation across the Napa Valley.

Conditions Temperatures Precipitation
Avg daytime high -5°C (23°F) cold → 32°C (90°F) hot

Marker color shows the average daytime high temperature in September: blue is cold, red is hot.

See all September weather averages, cities and regions in the Napa Valley

The Napa Valley temperatures in September: frequently asked questions

How hot does it get in the Napa Valley, the United States of America in September?

Average daytime highs in the Napa Valley, the United States of America during September reach about 30°C (86°F) in Napa.

How cold does it get at night in the Napa Valley, the United States of America in September?

Average overnight lows in the Napa Valley, the United States of America during September sit near 12°C (54°F) in Napa.

What is the warmest city in September in the Napa Valley, the United States of America?

Based on our systematic data collection, Calistoga has been identified as the city with the highest average temperatures. The daytime temperature usually hovers around 31°C (88°F), while at night it goes down to an approximate temperature of 11°C (52°F).

What is the coldest city in September in the Napa Valley, the United States of America?

Our database indicates that in September, American Canyon is the city with the coolest temperatures in the Napa Valley, the United States of America. You can expect daytime highs of 28°C (82°F) and nighttime lows close to 11°C (52°F).

How much sun does the Napa Valley, the United States of America get in September?

Napa usually sees around 275 hours of sunlight, indicating many sunny days.

Interested in more climate information?

We have much more information about the climate in the Napa Valley.

Weather and climate has detailed information for every country in the world. Are you going to the United States of America? Get detailed historical weather averages for many cities in the United States of America.

Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal travel conditions. Find out where to go with our weather planner.

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