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San Francisco September Weather

Averages and records for weather in San Francisco, California in the month of September.

Typical San Francisco September Weather 1991–2020
Average daily high	70.8 °F
Average daily low	55.9 °F
Average monthly precipitation	0.1 inches
Daily chance of precipitation	3.9%

San Francisco September Weather Records 1921–2024
Highest temperature	106 °F	September 1, 2017
Lowest temperature	48 °F	September 27, 1955
Highest daily low	75 °F	September 2, 2017
Lowest daily high	55 °F	September 7, 1975
Hottest average high temperature	81.2 °F	1984
Coldest average high temperature	63.4 °F	1962
Most daily precipitation	2.0 inches	September 18, 1959
Most monthly precipitation	2.1 inches	1959

Note: Daily averages are a moving average which includes 14 days before and after

Day	Average (°F)		Record (°F)
Day	High	Low	High	Low
September 1	69.6	56.1	106	51
September 2	69.6	56.1	102	50
September 3	69.7	56.1	92	50
September 4	69.9	56.1	93	50
September 5	70.1	56.1	96	50
September 6	70.2	56.1	100	50
September 7	70.3	56.1	91	51
September 8	70.3	56.1	100	50
September 9	70.4	56.0	100	50
September 10	70.5	56.0	89	50
September 11	70.6	56.0	98	50
September 12	70.7	56.0	98	49
September 13	70.8	56.0	99	50
September 14	70.8	55.9	101	50
September 15	70.8	55.9	94	51
September 16	70.8	55.9	89	51
September 17	70.7	55.8	93	51
September 18	70.8	55.8	91	49
September 19	70.8	55.8	92	49
September 20	70.7	55.8	97	50
September 21	70.6	55.7	99	51
September 22	70.6	55.7	97	49
September 23	70.7	55.7	97	49
September 24	70.8	55.6	95	50
September 25	70.9	55.6	94	50
September 26	70.9	55.6	94	48
September 27	70.8	55.5	93	48
September 28	71.0	55.5	95	49
September 29	71.2	55.5	93	49
September 30	71.4	55.5	96	49

Weather Station Details

Years	Station	Coordinates
1921–2024	Downtown San Francisco	location