Monthly climate guide
San Francisco weather in September
September in San Francisco is typically warm, with average daytime highs around 24°C (76°F) and night-time lows near 13°C (56°F). The month usually brings about 4 mm of rain (very dry) and is a mix of sun and cloud. Daytime highs are about the same as August and about the same as October.
What stands out in September
- In San Francisco, September is early autumn.
- Rain is well below San Francisco's usual level (around 91% less).
- Just 60 km apart, but San Francisco runs about 6°C cooler than Napa this month.
- Comfortable temperatures make it easy to walk between Fisherman's Wharf and Golden Gate Bridge.
September is typically San Francisco's warmest month.
Avg high
24°C
76°F
Avg low
13°C
56°F
Rainfall
4 mm
very dry
Humidity
71%
relative
Sky
46%
cloud · a mix of sun and cloud
San Francisco weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | 14°C / 57°F | 7°C / 44°F | 96 mm | 83% | 59% |
| February | 15°C / 59°F | 7°C / 45°F | 90 mm | 80% | 54% |
| March | 16°C / 60°F | 8°C / 47°F | 98 mm | 82% | 61% |
| April | 18°C / 64°F | 9°C / 48°F | 35 mm | 79% | 53% |
| May | 19°C / 66°F | 10°C / 50°F | 15 mm | 77% | 54% |
| June | 22°C / 72°F | 12°C / 53°F | 9 mm | 73% | 45% |
| July | 22°C / 72°F | 12°C / 54°F | 1 mm | 74% | 56% |
| August | 23°C / 74°F | 13°C / 55°F | 1 mm | 75% | 60% |
| September | 24°C / 76°F | 13°C / 56°F | 4 mm | 71% | 46% |
| October | 23°C / 73°F | 12°C / 54°F | 22 mm | 67% | 41% |
| November | 18°C / 64°F | 9°C / 48°F | 59 mm | 75% | 47% |
| December | 14°C / 57°F | 7°C / 44°F | 95 mm | 79% | 53% |
What to pack for September
- T-shirts plus a light layer for the evening
- Comfortable trainers or sandals for long walks
Is September a good time to visit San Francisco?
Our San Francisco guide recommends: September to November, when fog is less frequent and temperatures are at their warmest — summer here can be surprisingly cool and foggy.
Bring layers even in summer — Mark Twain's famous (if apocryphal) line about a cold San Francisco summer is closer to true than visitors expect.
Best time to visit San Francisco →Other United States cities in September
Cite or embed this data
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San Francisco weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/usa/san-francisco/september
<a href="https://weathercompare.eu/weather/usa/san-francisco/september">San Francisco weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/usa/san-francisco" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="San Francisco weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/usa/san-francisco/september">San Francisco weather in September</a> – WeatherCompare</p>
San Francisco in September: quick answers
Is September a good time to visit San Francisco?
Yes. September is one of the best months for San Francisco, with highs around 24°C and about 4 mm of rain.
How warm is San Francisco in September?
Average highs are about 24°C (76°F) and average lows about 13°C (56°F), based on 10 years of daily data.
Does it rain a lot in San Francisco in September?
San Francisco typically gets around 4 mm of rain in September — very dry.
When is the best time to visit San Francisco?
September to November, when fog is less frequent and temperatures are at their warmest — summer here can be surprisingly cool and foggy.
Figures are long-term averages for the area around San Francisco (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.