Is San Francisco hot in September?
Days are typically hot at 31.1°C, while nights average 25.8°C.
Colombia · 1991–2020 normal
San Francisco in
September.
Typical September weather in San Francisco: 31.1°C by day, 25.8°C at night, 205 mm of rain over 15.5 wet days. These are measured 1991–2020 station normals, not a forecast.
Typical high31.1°C
Typical low25.8°C
Rain205 mm
Wet days15.5
In the year-round weather comparison, September scores 22 out of 100 (March leads the year at 61). Daylight is calculated as 12 h 11 from latitude 12.52°. Open-water sea temperature is 29.0°C (15 km from the place centre).
September at a glance
What is San Francisco like in September?
Plain answers from the measured climate record—not a forecast or a promise about a particular trip.
Does it rain much?
The measured monthly average is 205 mm across about 16 wet days.
How much daylight is there?
There are about 12 h 11 between sunrise and sunset at mid-month, calculated from the place latitude.
Is September a good time to visit?
September ranks 10 of 12 in our weather comparison; March ranks first.
Event window
Warm sea in September
The nearest open-water NOAA OISST 1991–2020 cell averages 29.0°C in September. A sheltered bay can run warmer than that open-water cell.
The evidence behind this page
One month,
from the same station.
- Place identity
- GeoNames 3669843
- NOAA station
- CO000080001 · SAN ANDRES (ISLA)/S
- Station distance
- 7.6 km from the place centre
- Coverage
- Good coverage · 19 usable years
- Important limit
- Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.
Next step
Choose your month.
Then plan the details.
The weather comparison for San Francisco is based on climate evidence, not payments from travel companies. Flight, accommodation and activity links will be clearly labelled when they are added; there are no booking offers on this page today.
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