Weathermondo.com
United StatesThe weather in September in Napa
It's warm in September in Napa with an average temperature of 28°C. Temperatures this month range from a low of 24°C to a high of 31°C. At night, you can expect temperatures between 10°C and 14°C.
Looking for great weather? September is a good time to be in Napa. The temperatures are nice, and there’s not too much rain.
Average temperatures and precipitation
This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for Napa, California. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.
Temperature records
With 44°C in 2022, Napa reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 18°C in 2020. The extreme nighttime temperatures ranged from a lowest recorded value of 4°C to a highest value of 22°C.
Rainfall amount
According to weather history, there is only 3,1 mm of precipitation in September. The wind speed is around 4 Bft, mostly coming from the Southwest.
Daily weather in September for Napa
Click on any day in September to get detailed info about the usual weather on that day in Napa. Check out the historical temperatures and precipitation over the past 10 years on this day.
September weather comparison
| Napa | New York | |
|---|---|---|
| Average temperature | 28°C | 27°C |
| Max. temperature | 31°C | 31°C |
| Min. temperature | 10°C | -5°C |
| Total precipitation | 3,1 mm | 57 mm |
| Rainy days | 1 day | 9 days |
Start of September
The month of September starts in Napa with hot temps, averaging around 29°C during the day and nights around 14°C.
Mid September
By mid-September, daytime temps drop to around 27°C, with nights around 13°C. No precipitation expected during this period, so you can enjoy plenty of sunshine.
End of September
By the end of September, the average daytime temperature in Napa is around 28°C, while nighttime temps are about 12°C. No precipitation expected at the end of the month; it’ll be mostly sunny.
UV index
The UV index is a maximum of 8 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
Check out the climate of Napa for all months and discover the best travel time
Temperature charts
These charts show the average temperatures in September in Napa, California. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.
Daily Temperature in September in Napa
Temperature in September in Napa over the years
Precipitation charts
These charts show the average amount of precipitation in September in Napa, California. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.
Daily Precipitation in September in Napa
Total precipitation in September in Napa over the years
Daily UV index in September in Napa
This chart shows the average daily UV index in September in Napa, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Weather experiences in September in Napa
Have you been to Napa in September?
Share your weather experience in September in Napa.
Average weather in Napa by month
Click on a month below to see detailed weather info for Napa. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.