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St. Helena September Weather

Averages and records for weather in St. Helena, California in the month of September.

Typical St. Helena September Weather 1991–2020
Average daily high	86.5 °F
Average daily low	53.1 °F
Average monthly precipitation	0.1 inches
Average monthly snow	none
Daily chance of precipitation	1.7%
Daily chance of snow	0%

St. Helena September Weather Records 1907–2023
Highest temperature	113 °F	September 6, 2022
Lowest temperature	33 °F	September 29, 1929
Highest daily low	74 °F	September 17, 1968
Lowest daily high	49 °F	September 8, 1920
Hottest average high temperature	93.9 °F	1922
Coldest average high temperature	69.1 °F	1920
Most daily precipitation	3.7 inches	September 18, 1959
Most monthly precipitation	3.7 inches	1959
Most daily snow	none	-
Most monthly snow	none	-

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	88.2	54.7	113	40
September 2	88.0	54.5	113	41
September 3	87.9	54.4	112	40
September 4	87.9	54.4	107	37
September 5	87.8	54.3	112	39
September 6	87.8	54.2	113	43
September 7	87.7	54.1	110	40
September 8	87.6	54.0	109	41
September 9	87.5	53.8	112	38
September 10	87.5	53.7	105	40
September 11	87.3	53.6	104	38
September 12	87.2	53.6	107	40
September 13	87.1	53.4	110	35
September 14	87.0	53.4	111	35
September 15	86.8	53.3	106	37
September 16	86.6	53.2	109	37
September 17	86.3	53.1	107	40
September 18	86.1	52.9	106	38
September 19	85.8	52.8	104	33
September 20	85.5	52.7	107	35
September 21	85.1	52.6	108	36
September 22	84.8	52.4	108	37
September 23	84.6	52.3	107	39
September 24	84.5	52.1	106	37
September 25	84.4	52.0	101	35
September 26	84.1	51.9	103	33
September 27	83.8	51.7	108	37
September 28	83.6	51.5	106	35
September 29	83.5	51.3	100	33
September 30	83.4	51.2	101	35

Weather Station Details

Years	Station	Coordinates
1907–2023	Saint Helena	location