San Francisco Intl AP Threshold Days by Year (USW00023234)

11 fixed thresholds counted per year at San Francisco Intl AP (USW00023234): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for San Francisco Intl AP Thresholds

San Francisco Intl AP: days with 10 mm (0.39 in) or more of precipitation in 81 years, most in 1983 with 40.
San Francisco Intl AP: days with a maximum temperature at or above 30 C (86 F) in 80 years, most in 2020 with 21.
San Francisco Intl AP: days with 25 mm (0.98 in) or more of precipitation in 77 years, most in 1952 with 11.
San Francisco Intl AP: days with a maximum temperature at or above 90 F (32.2 C) in 74 years, most in 1984 with 12.
11 fixed thresholds have at least one qualifying day at San Francisco Intl AP.

Days at or above 30 C (86 F)

80 years with a qualifying day

Days per year at San Francisco Intl AP with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 21 in 2020.

Days at or above 30 C (86 F) per year at San Francisco Intl AP
Year	Days	Decade average
1946	7	5.3
1947	7	5.3
1948	2	5.3
1949	5	5.3
1950	6	7
1951	5	7
1952	6	7
1953	5	7
1954	6	7
1955	4	7
1956	5	7
1957	7	7
1958	15	7
1959	11	7
1960	7	6.9
1961	14	6.9
1962	4	6.9
1963	7	6.9
1964	10	6.9
1965	4	6.9
1966	7	6.9
1967	7	6.9
1968	7	6.9
1969	2	6.9
1970	16	10
1971	8	10
1972	6	10
1973	12	10
1974	11	10
1975	7	10
1976	16	10
1977	4	10
1978	11	10
1979	9	10
1980	8	9.6
1981	11	9.6
1982	4	9.6
1983	17	9.6
1984	20	9.6
1985	11	9.6
1986	1	9.6
1987	7	9.6
1988	9	9.6
1989	8	9.6
1990	5	7.7
1991	8	7.7
1992	7	7.7
1993	11	7.7
1994	5	7.7
1995	11	7.7
1996	10	7.7
1997	6	7.7
1998	4	7.7
1999	10	7.7
2000	9	9.8
2001	10	9.8
2002	11	9.8
2003	15	9.8
2004	12	9.8
2005	3	9.8
2006	6	9.8
2007	2	9.8
2008	15	9.8
2009	15	9.8
2010	15	10.2
2011	6	10.2
2012	5	10.2
2013	2	10.2
2014	15	10.2
2015	13	10.2
2016	7	10.2
2017	13	10.2
2019	16	10.2
2020	21	9.6
2021	7	9.6
2022	10	9.6
2023	9	9.6
2024	13	9.6
2025	1	9.6
2026	6	9.6

For each year, a bar from the first to the last day at San Francisco Intl AP meeting 30 C (86 F).

First to last qualifying date each year at San Francisco Intl AP
Year	First date	Last date
1946	1946-06-18	1946-10-11
1947	1947-04-12	1947-09-21
1948	1948-07-14	1948-09-13
1949	1949-05-06	1949-09-22
1950	1950-05-29	1950-09-21
1951	1951-05-25	1951-10-07
1952	1952-05-19	1952-10-01
1953	1953-06-24	1953-10-05
1954	1954-06-21	1954-10-14
1955	1955-05-28	1955-09-03
1956	1956-05-16	1956-09-28
1957	1957-04-28	1957-09-07
1958	1958-05-15	1958-10-10
1959	1959-06-29	1959-10-24
1960	1960-06-01	1960-09-25
1961	1961-06-15	1961-10-16
1962	1962-06-18	1962-09-16
1963	1963-07-25	1963-09-26
1964	1964-06-22	1964-09-24
1965	1965-10-01	1965-10-24
1966	1966-06-13	1966-10-09
1967	1967-05-16	1967-10-16
1968	1968-07-18	1968-09-25
1969	1969-09-07	1969-09-25
1970	1970-05-15	1970-10-01
1971	1971-08-23	1971-10-12
1972	1972-05-13	1972-10-06
1973	1973-05-28	1973-09-28
1974	1974-05-26	1974-10-17
1975	1975-05-28	1975-09-24
1976	1976-05-12	1976-10-12
1977	1977-07-29	1977-08-29
1978	1978-05-19	1978-10-13
1979	1979-05-12	1979-09-12
1980	1980-06-27	1980-10-03
1981	1981-04-28	1981-08-27
1982	1982-05-23	1982-09-12
1983	1983-05-19	1983-09-20
1984	1984-04-14	1984-09-28
1985	1985-06-10	1985-10-04
1986	1986-06-09	1986-06-09
1987	1987-05-05	1987-10-06
1988	1988-04-10	1988-10-17
1989	1989-04-06	1989-10-08
1990	1990-06-08	1990-10-03
1991	1991-07-01	1991-10-20
1992	1992-07-09	1992-10-10
1993	1993-05-09	1993-10-26
1994	1994-06-09	1994-09-16
1995	1995-06-24	1995-10-02
1996	1996-04-29	1996-10-08
1997	1997-05-16	1997-09-29
1998	1998-07-15	1998-08-04
1999	1999-06-30	1999-10-10
2000	2000-05-21	2000-09-19
2001	2001-05-07	2001-10-14
2002	2002-06-05	2002-10-07
2003	2003-06-25	2003-10-27
2004	2004-04-25	2004-10-13
2005	2005-07-23	2005-08-31
2006	2006-05-14	2006-08-09
2007	2007-05-07	2007-09-05
2008	2008-05-14	2008-09-06
2009	2009-04-19	2009-09-26
2010	2010-06-12	2010-10-14
2011	2011-06-20	2011-09-28
2012	2012-06-16	2012-10-18
2013	2013-05-02	2013-09-07
2014	2014-04-29	2014-10-13
2015	2015-04-30	2015-10-13
2016	2016-04-06	2016-09-26
2017	2017-05-03	2017-10-26
2019	2019-04-23	2019-10-25
2020	2020-05-25	2020-10-17
2021	2021-06-16	2021-10-03
2022	2022-04-07	2022-10-19
2023	2023-08-20	2023-10-19
2024	2024-07-02	2024-10-07
2025	2025-09-23	2025-09-23
2026	2026-03-20	2026-10-03

Every Fixed Threshold

Fixed thresholds at San Francisco Intl AP
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	80	21	2020	6
35 C (95 F): Days	34	5	2020	1
40 C (104 F): Days	2	2	2017	2
90 F (32.2 C): Days	74	12	1984	4
100 F (37.8 C): Days	7	2	1971	1
0 C (32 F): Frost days (min	32	17	1949	1
20 C (68 F): Tropical nights (min	3	3	2017	1
10 mm (0.39 in): Days with 10 mm or more rain	81	40	1983	10
25 mm (0.98 in): Days with 25 mm or more rain	77	11	1952	4
50 mm (1.97 in): Days with 50 mm or more rain	32	3	1962	1
100 mm (3.94 in): Days with 100 mm or more rain	3	1	1967	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1946.

Download the Data

Data for San Francisco Intl AP threshold days by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-17 (17 October 2026). Threshold counts are computed by this site.

Data as of 2026-10-17. Last revised 17 October 2026 (2026-10-17).

San Francisco Intl AP Threshold Days by Year (USW00023234)

Key Facts for San Francisco Intl AP Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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