United StatesAverage weather for San Francisco in September
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.
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. No precipitation expected at the start of the month; it’ll be sunny.
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.
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.
San Francisco in September |
New York | ||
|---|---|---|---|
 Average temperature |
24°C | 27°C | |
 Max. temperature |
27°C | 31°C | |
| Min. temperature |
21°C | -5°C | |
 Total precipitation |
2,5 mm | 57 mm | |
| Rainy days |
1 day | 9 days | |
August
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.
Is September a good time to visit San Francisco?
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.
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.
Check out the climate of San Francisco for all months and discover the best travel time
Daily Temperature in September in San Francisco
This chart shows the average daily high and low temperatures in September for San Francisco, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.
Daily Precipitation in September in San Francisco
The chart below shows the average daily precipitation in September for San Francisco, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for September, you can expect about 1 day of precipitation in San Francisco.
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.
Temperature in September in San Francisco over the years
This chart shows the average temperature in September in San Francisco, measured in degrees Celsius, over the past few years.
Total precipitation in September in San Francisco over the years
This chart shows the average precipitation in September in San Francisco, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.
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.
Weather experiences in September in San Francisco
Have you been to San Francisco in September?
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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.
Or check out the climate of San Francisco for all months at once
