San Francisco weather in September
San Francisco in September averages 18°C (65°F) and 2 mm of rain. It is one of the driest months of the year here.
Of the twelve months in San Francisco, September is the warmest and the third driest.
- Average temp
- 18°C (65°F)
14–23°C · 56–74°F
- Rainfall
- 2 mm
Not much rain
- Sunshine
- —
- Wind
- 18 km/h
What is San Francisco like in September?
Daytime
Days are mild.
Rain
Rain is usually light.
Evening
Evenings are cooler. A layer helps after sunset.
What should I pack for San Francisco in September?
A layer for the evening
Evenings cool off noticeably once the sun is down.
September compared with August and October
September in San Francisco is about the same temperature as August and about as wet as it, which averages 18°C (65°F).
September in San Francisco is 1.3°C warmer than October and 17 mm drier than it, which averages 17°C (63°F).
Daylight in San Francisco in September
On 15 September the sun is up for 12 hours 24 minutes in San Francisco, rising about 06:52 and setting about 19:16 local time.
September ends 1 hour 10 minutes shorter than it begins, so the last week of the month is a different length of day from the first.
That is 2 hours 22 minutes short of June, the longest-lit month here.
Where to stay in San Francisco
Dates are a starting point for September.
Travel guides for San Francisco
What to read before you book.
San Francisco weather by month
TemperatureRainfall
How September compares with the rest of the year
September is highlighted. Every other month links to its own page.
| Month | Average | Rainfall |
|---|---|---|
| January | 11°C / 51°F | 99 mm |
| February | 12°C / 53°F | 100 mm |
| March | 13°C / 55°F | 69 mm |
| April | 14°C / 57°F | 35 mm |
| May | 15°C / 60°F | 13 mm |
| June | 17°C / 62°F | 4 mm |
| July | 18°C / 64°F | 0 mm |
| August | 18°C / 65°F | 1 mm |
| September | 18°C / 65°F | 2 mm |
| October | 17°C / 63°F | 19 mm |
| November | 13°C / 56°F | 50 mm |
| December | 11°C / 51°F | 106 mm |
Check another month
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FAQs about San Francisco in September
September climate averages for San Francisco, 1991–2020.
San Francisco averages 18°C (65°F) in September, ranging from about 14°C (56°F) at night to 23°C (74°F) in the afternoon. That is a 1991–2020 average, so an individual week can run either side of it.
Barely. September sees only about 2 mm, so rain is unlikely to affect your plans.
Yes. September averages 18°C (65°F) against 17°C (63°F) in October — 1.3°C warmer.
September is about as warm as August, and about as wet.
Yes. September falls inside the most comfortable stretch of the year here, May to October, on temperature and rainfall together.
This page does not show today's weather. It is a 1991–2020 climate normal from Meteostat — a long-run average of what September is usually like, which is what you want when booking months ahead. For today or the coming week, check a live forecast.
About 12 hours 24 minutes of daylight in mid-September, against 14 hours 46 minutes in June and 9 hours 34 minutes in December.
On 15 September, sunrise is about 06:52 and sunset about 19:16 local time. Both shift across the month — the month ends 1 hour 10 minutes shorter than it starts.
