Average September Temperature in Half Moon Bay by Year

This page contains a list of the average monthly high and low temperatures in Half Moon Bay, California for the month of September each year between 1939 and 2023. It is based on NOAA data.

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What Was the Hottest September Ever in Half Moon Bay?

2014 was the warmest September in the history of Half Moon Bay, California. The average daily high temperature was 69.1 °F, and the average low was 57.3 °F.

What Was the Coldest September Ever in Half Moon Bay?

1955 was the coolest September in the history of Half Moon Bay, California. The average daily high temperature was 62.0 °F, and the average low was 47.8 °F.

* click column headers to sort

Year	Rank	High (°F)	Low (°F)
2023	25	65.6	54.0
2022	23	66.3	53.5
2021	50	64.4	52.5
2020	12	67.3	54.3
2019	11	68.7	52.9
2018	70	63.1	51.2
2017	3	71.3	54.3
2016	55	66.3	50.4
2015	22	69.0	50.9
2014	1	69.1	57.3
2013	18	68.1	52.4
2012	77	62.3	49.8
2011	58	65.2	51.1
2010	60	66.1	49.7
2009	44	66.6	50.8
2008	71	66.2	48.0
2007	49	67.4	49.6
2006	75	64.9	47.5
2005	67	64.2	50.4
2004	65	68.5	46.5
2001	61	64.8	51.0
2000	14	69.2	52.1
1999	45	65.6	51.7
1998	37	64.9	53.3
1997	2	70.5	55.4
1996	68	64.4	50.1
1995	31	66.2	52.7
1994	21	66.2	54.0
1992	48	66.7	50.3
1991	62	63.6	52.1
1990	24	66.7	53.0
1989	40	65.7	52.0
1988	72	66.6	47.3
1987	43	66.3	51.4
1986	42	65.7	52.0
1985	33	66.1	52.5
1984	10	71.0	50.9
1982	35	67.7	50.8
1981	52	66.0	50.8
1980	53	65.1	51.6
1979	6	71.9	52.0
1978	29	69.7	49.6
1976	20	67.6	52.6
1975	73	62.6	51.2
1974	32	65.5	53.2
1973	38	65.9	52.3
1972	17	68.2	52.4
1971	41	67.1	50.6
1970	56	70.3	46.3
1969	66	64.1	50.6
1968	36	68.2	50.2
1967	8	68.1	55.1
1966	28	69.5	49.9
1965	46	64.7	52.6
1964	51	66.2	50.6
1962	69	63.3	51.1
1961	16	68.0	52.6
1960	64	64.3	51.1
1959	26	67.1	52.6
1958	4	72.3	51.7
1957	15	67.4	53.4
1956	27	68.0	51.6
1955	78	62.0	47.8
1954	63	66.1	49.5
1953	9	67.3	55.2
1952	13	69.5	51.8
1951	34	64.8	53.8
1950	57	65.1	51.3
1948	74	64.6	48.6
1947	39	67.0	51.1
1946	47	66.9	50.3
1945	59	66.4	49.4
1944	76	63.7	48.5
1943	19	67.4	52.9
1942	54	65.0	51.7
1941	30	69.0	50.0
1940	5	69.8	54.1
1939	7	70.8	52.9

Weather Station Details

Years	Station	Coordinates
1939–2024	Half Moon Bay	location