San Francisco in September
8.4out of 10
Yes, a good time to go
Warm and comfortable: highs around 23°C. Some rain: about 5 rainy days.
23°CAvg high
11°CAvg low
5Rainy days (51 mm)
11:49 hDaylight
07:08Sunrise · 18:57 Sunset
Why this score
- Warm and comfortable: highs around 23°C
- Some rain: about 5 rainy days
What to wear and pack
- T-shirts and light layers
- A light jacket for cooler evenings
How reliable is the forecast?
Rainfall in September is fairly consistent from year to year (2.6 days). Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 30°C | 19°C | 120 mm | 9 | – | – | 7.3 |
| February | 29°C | 18°C | 116 mm | 9 | – | – | 7.7 |
| March | 27°C | 17°C | 138 mm | 9 | – | – | 7.6 |
| April | 24°C | 14°C | 100 mm | 8 | – | – | 7.9 |
| May | 21°C | 11°C | 47 mm | 6 | – | – | 8.1 |
| June | 18°C | 8°C | 30 mm | 4 | – | – | 7.8 |
| July | 17°C | 6°C | 20 mm | 3 | – | – | 7.9 |
| August | 20°C | 8°C | 39 mm | 4 | – | – | 8.3 |
| September | 23°C | 11°C | 51 mm | 5 | – | – | 8.4 |
| October | 25°C | 14°C | 115 mm | 9 | – | – | 7.7 |
| November | 28°C | 16°C | 119 mm | 9 | – | – | 7.7 |
| December | 30°C | 18°C | 128 mm | 10 | – | – | 7.4 |
Frequently asked questions
How hot is San Francisco in September?
Daytime highs average 23°C and nights about 11°C.
When is the best time to visit San Francisco?
The best months are September, August, May, April.