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United StatesThe weather in September in San Francisco
It's warm in September in San Francisco with an average temperature of 24°C. Temperatures this month range from a low of 21°C to a high of 27°C. At night, you can expect temperatures between 14°C and 16°C.
Looking for great weather? September is a good time to be in San Francisco. The temperatures are nice, and there’s little chance of rain this month.
Average temperatures and precipitation
This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for San Francisco, 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 38°C in 2017, San Francisco reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 16°C in 2016. The extreme nighttime temperatures ranged from a lowest recorded value of 9°C to a highest value of 22°C.
Rainfall amount
According to weather history, there is only 2,5 mm of precipitation in September. The wind speed is around 5 Bft, mostly coming from the West.
Daily weather in September for San Francisco
Click on any day in September to get detailed info about the usual weather on that day in San Francisco. Check out the historical temperatures and precipitation over the past 10 years on this day.
September weather comparison
| San Francisco | New York | |
|---|---|---|
| Average temperature | 24°C | 27°C |
| Max. temperature | 27°C | 31°C |
| Min. temperature | 14°C | -5°C |
| Total precipitation | 2,5 mm | 57 mm |
| Rainy days | 1 day | 9 days |
Start of September
The month of September starts in San Francisco with warm temps, averaging around 25°C during the day and nights around 16°C.
Mid September
By mid-September, daytime temps drop to around 24°C, with nights around 16°C. Not much precipitation expected during this period. It’s mostly dry and sunny.
End of September
By the end of September, the average daytime temperature in San Francisco is around 24°C, while nighttime temps are about 15°C. There’s hardly any chance of precipitation. The weather will be mostly dry with plenty of sun.
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UV index
The UV index is a maximum of 6 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Check out the climate of San Francisco for all months and discover the best travel time
Temperature charts
These charts show the average temperatures in September in San Francisco, California. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.
Daily Temperature in September in San Francisco
Temperature in September in San Francisco over the years
Precipitation charts
These charts show the average amount of precipitation in September in San Francisco, 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 San Francisco
Total precipitation in September in San Francisco over the years
Daily UV index in September in San Francisco
This chart shows the average daily UV index in September in San Francisco, 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 San Francisco
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Average weather in San Francisco by month
Click on a month below to see detailed weather info for San Francisco. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.