San Francisco Weather in September

What's the weather like in San Francisco (California) in September 2023?

The climate in San Francisco during September can be summarized as mild and very dry.

September is in the fall / autumn in San Francisco and is typically the warmest month of the year. Daytime maximum temperatures average around 22°C (71°F), whilst at night 13°C (55°F) is normal.

San Francisco weather averages (imperial / metric)
Daytime temperature 21.6°C 70.9°F
Nightly temperature 13°C 55.4°F
Average temperature 17.3°C 63.1°F
Daily sunshine 9.9 hrs
Avg rainfall 7 mm 0.3 ins
Rainy days 2 days
Sea temperature 14.4°C 57.9°F
Humidity 70%
Windspeed 16.6kph 10 mph

On average September is the 4th driest month of the year in San Francisco with around 7mm 0.3 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 9.9 hours of sunshine per day.

September temperatures in San Francisco

San Francisco average temperature in September

September rainfall

San Francisco average rain in September

September hourly sunshine

San Francisco average rain in September

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in San Francisco in September 2023.