What to pack for San Francisco in September
- t-shirts and light layers
- a light jacket for evenings
Humidity averages 80%; max daily wind around 28 km/h.
How September compares
Best months in San Francisco: April–October. See the full best time to visit San Francisco guide.
San Francisco in September: the details
In September, San Francisco sees average daytime highs of 21°C (69°F) and overnight lows of 14°C (58°F). Rainfall totals roughly 5 mm across 1.3 rainy days, and the sun shines about 11.3 hours per day with 12.2 hours of daylight mid-month. Relative humidity averages 80%.
In context: September is the warmest month of the year and the 9th-wettest in San Francisco. The sunniest month is June (13.2 h/day).
| Metric | September average |
|---|---|
| Daytime high | 21°C / 69°F |
| Overnight low | 14°C / 58°F |
| Rainfall | 5 mm over 1.3 rainy days |
| Sunshine | 11.3 h/day (12.2 h daylight) |
| Humidity | 80% |
| Travel score | 10.0 / 10 |
These figures are climate normals computed from the ERA5 weather reanalysis (2019–2024) for San Francisco, United States (37.77, -122.42) — see our methodology. Actual conditions vary year to year.
Not set on San Francisco? Browse the best places to visit in September ranked by travel score.
Frequently asked questions
How hot is San Francisco in September?
Daytime highs in San Francisco in September average 21°C (69°F); nights drop to about 14°C.
Does it rain in San Francisco in September?
Expect around 1.3 rainy days and 5 mm of rainfall in September.
Is September a good time to visit San Francisco?
September is one of the best months to visit San Francisco. Overall travel score: 10.0/10. The best months are April–October.
Also good in September, near San Francisco
Where should you go next month?
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