San Francisco Weather in September
What's the weather like in San Francisco (Departamento de Antioquia) in September 2025?
The climate in San Francisco during September can be summarized as warm, humid and very wet.
September is in the fall / autumn in San Francisco and is typically the 3rd coldest month of the year. Daytime maximum temperatures average around a muggy 27°C (80°F), whilst at night 16°C (60°F) is normal.
| Daytime temperature | 26.9°C 80.4°F |
|---|---|
| Nightly temperature | 15.5°C 59.9°F |
| Average temperature | 21.2°C 70.2°F |
| Daily sunshine | 5 hrs |
| Avg rainfall | 224 mm 8.8 ins |
| Rainy days | 22 days |
| Sea temperature | 28°C 82.4°F |
| Humidity | 75% |
| Windspeed | 11.2kph 7 mph |
On average September is the 5th wettest month of the year in San Francisco with around 224mm 8.8 inches of rain making it a very wet time to visit. This rainfall is typically spread over 22 days, although this may vary considerably.
On the flip side this corresponds to an average of 5 hours of sunshine per day.
September temperatures in San Francisco
September rainfall
September hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in San Francisco in September 2025.
Other monthly averages
Best places to visit in September
San Francisco weather stats
| Hottest month: | March | 27.8°C 82°F |
|---|---|---|
| Driest month: | February | 106mm 4.2ins |
| Sunniest month: | January | 6.3hrs |
| Coldest month: | October | 26.2°C 79.2°F |
| Wettest month: | October | 285mm 11.2ins |
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