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Weather in San Francisco, California for September 2025

Your guide to San Francisco weather in September - trends and predictions

    Temperatures

  • Until now, September 2025 in San Francisco has been significantly cooler than historical averages by -5.1 °F, with average temperature of 16.1 °F.

  • Expect cooler weather in the next days in San Francisco with the forecast suggesting a temperature of 19.1 °F, lower than the historical average.

  • In general, the average temperature in San Francisco at the beginning of September is 21.6 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 19.7 °F by the end of September.

  • Rain 🌧️

  • Precipitation in San Francisco during September is a rare event, with an average of fewer than 2 rainy days.

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Average dry days
29
Dry days
Average rainy days
1
Rainy days
Average snowy days
0
Snow days
Average temperatures
20°/13°
Temperatures
Average wind speed
16 km/h
Avg max wind
Average humidity
76 %
Avg humidity

San Francisco Weather September

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Temperatures trend during September in San Francisco

See the weather trend as well as the moving average line

September weather in San Francisco day by day

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Date Weather Temperatures Rain UV More
Sept. 1 Cloudy
Cloudy
20° /12° 0 mm 4
Sept. 2 Sunny
Sunny
19° /13° 0 mm 5
Sept. 3 Sunny
Sunny
22° /13° 0 mm 6
Sept. 4 Sunny
Sunny
22° /13° 0 mm 6
Sept. 5 Sunny
Sunny
23° /14° 0 mm 6
Sept. 6 Sunny
Sunny
23° /13° 0 mm 6
Sept. 7 Sunny
Sunny
22° /13° 0 mm 6
Sept. 8 Sunny
Sunny
23° /13° 0 mm 6
Sept. 9 Sunny
Sunny
21° /13° 0 mm 5
Sept. 10 Partly cloudy
Partly cloudy
19° /13° 0 mm 5
Sept. 11 Sunny
Sunny
20° /13° 0.1 mm 5
Sept. 12 Sunny
Sunny
20° /13° 0 mm 5
Sept. 13 Sunny
Sunny
20° /12° 0 mm 5
Sept. 14 Partly cloudy
Partly cloudy
19° /15° 0 mm 1.7
Sept. 15 Partly cloudy
Partly cloudy
18° /14° 0 mm 1.8
Sept. 16 Mist
Mist
18° /13° 0 mm 1.7
Sept. 17 Sunny
Sunny
23° /16° 0 mm 1.7
Sept. 18 Partly cloudy
Partly cloudy
18° /15° 0 mm 0
Sept. 19 Sunny
Sunny
19° /15° 0 mm 5
Sept. 20 Partly cloudy
Partly cloudy
19° /15° 0 mm 5
Sept. 21 Sunny
Sunny
19° /15° 0 mm 5
Sept. 22 Sunny
Sunny
20° /15° 0 mm 5
Sept. 23 Sunny
Sunny
19° /15° 0 mm 5
Sept. 24 Partly cloudy
Partly cloudy
18° /15° 0 mm 5
Sept. 25 Sunny
Sunny
19° /14° 0 mm 5
Sept. 26 Sunny
Sunny
19° /15° 0 mm 5
Sept. 27 Sunny
Sunny
20° /15° 0 mm 5
Sept. 28 Sunny
Sunny
19° /11° 0 mm 5
Sept. 29 Partly cloudy
Partly cloudy
20° /12° 0 mm 6
Sept. 30 Sunny
Sunny
23° /12° 0.5 mm 6
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Important Notice
Our weather forecast for San Francisco in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the San Francisco forecast closer to your planned date for the most up-to-date weather information.

San Francisco in September - FAQ

What are the expected maximum and minimum temperatures in San Francisco during September?
Enjoy moderate daytime temperatures of up to 20° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in San Francisco during September?
Rainfall in San Francisco during September is rare to nonexistent, with the total expected rainfall being less than 10 mm and approximately 1 days seeing any precipitation. Planning without the concern for rain is generally straightforward during this very dry period.
What are the typical wind conditions in San Francisco during September?
The average wind speed in San Francisco during September is 16 km/h, suggesting breezy to windy conditions, depending on your activities.

UV exposure in San Francisco during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️

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Location coordinates Where is San Francisco?

Get accurate weather forecasts for San Francisco, located at latitude 37.775 and longitude -122.419. Stay updated with localized weather information tailored for San Francisco.

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