San Francisco Threshold Days by Year

13 fixed thresholds counted per year at San Francisco (MXN00007145): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for San Francisco Thresholds

San Francisco: days with 10 mm (0.39 in) or more of precipitation in 50 years, most in 2002 with 86.
San Francisco: days with 25 mm (0.98 in) or more of precipitation in 48 years, most in 2003 with 36.
San Francisco: days with a maximum temperature at or above 30 C (86 F) in 43 years, most in 2008 with 350.
San Francisco: days with a maximum temperature at or above 35 C (95 F) in 43 years, most in 2009 with 142.
13 fixed thresholds have at least one qualifying day at San Francisco.

Days at or above 30 C (86 F)

43 years with a qualifying day

Days per year at San Francisco with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 350 in 2008.

Days at or above 30 C (86 F) per year at San Francisco
Year	Days	Decade average
1951	307	263.8
1952	308	263.8
1953	242	263.8
1954	257	263.8
1955	242	263.8
1956	227	263.8
1964	264	265.2
1965	264	265.2
1966	255	265.2
1967	266	265.2
1968	266	265.2
1969	276	265.2
1970	250	275.6
1971	284	275.6
1972	333	275.6
1973	284	275.6
1974	274	275.6
1975	256	275.6
1976	270	275.6
1977	308	275.6
1978	278	275.6
1979	219	275.6
1985	218	218
1990	254	287.9
1991	277	287.9
1992	295	287.9
1993	311	287.9
1994	339	287.9
1995	306	287.9
1997	290	287.9
1998	281	287.9
1999	238	287.9
2000	265	287.6
2001	255	287.6
2002	263	287.6
2003	246	287.6
2005	253	287.6
2006	327	287.6
2008	350	287.6
2009	342	287.6
2010	330	307
2011	321	307
2012	270	307

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

First to last qualifying date each year at San Francisco
Year	First date	Last date
1951	1951-01-01	1951-12-31
1952	1952-01-01	1952-12-31
1953	1953-01-01	1953-12-31
1954	1954-01-01	1954-12-31
1955	1955-01-01	1955-12-08
1956	1956-01-17	1956-12-24
1964	1964-01-20	1964-12-12
1965	1965-01-22	1965-12-28
1966	1966-01-01	1966-12-31
1967	1967-01-01	1967-12-31
1968	1968-01-01	1968-12-31
1969	1969-01-01	1969-12-31
1970	1970-01-01	1970-12-31
1971	1971-01-01	1971-12-31
1972	1972-01-01	1972-12-31
1973	1973-01-01	1973-12-31
1974	1974-01-01	1974-12-31
1975	1975-01-02	1975-12-30
1976	1976-01-01	1976-12-31
1977	1977-01-01	1977-12-31
1978	1978-01-01	1978-12-31
1979	1979-01-01	1979-12-24
1985	1985-02-03	1985-12-31
1990	1990-01-11	1990-12-31
1991	1991-01-01	1991-12-31
1992	1992-01-01	1992-12-30
1993	1993-01-03	1993-12-31
1994	1994-01-01	1994-12-31
1995	1995-01-04	1995-12-22
1997	1997-01-01	1997-12-31
1998	1998-01-05	1998-12-28
1999	1999-01-01	1999-12-20
2000	2000-01-02	2000-12-27
2001	2001-01-07	2001-12-25
2002	2002-01-05	2002-12-26
2003	2003-01-01	2003-12-13
2005	2005-01-02	2005-12-31
2006	2006-01-01	2006-12-31
2008	2008-01-01	2008-12-31
2009	2009-01-01	2009-12-31
2010	2010-01-01	2010-12-31
2011	2011-01-01	2011-12-31
2012	2012-01-01	2012-12-30

Every Fixed Threshold

Fixed thresholds at San Francisco
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	43	350	2008	270
35 C (95 F): Days	43	142	2009	42
40 C (104 F): Days	9	14	1965	6
90 F (32.2 C): Days	43	282	2009	91
100 F (37.8 C): Days	36	39	1965	6
110 F (43.3 C): Days	1	1	1998	1
0 C (32 F): Frost days (min	1	0	n/a	1
20 C (68 F): Tropical nights (min	43	258	1990	24
25 C (77 F): Days with min	1	2	1990	2
10 mm (0.39 in): Days with 10 mm or more rain	50	86	2002	61
25 mm (0.98 in): Days with 25 mm or more rain	48	36	2003	16
50 mm (1.97 in): Days with 50 mm or more rain	38	11	1978	3
100 mm (3.94 in): Days with 100 mm or more rain	11	2	1973	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1951.

Download the Data

Data for San Francisco 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 2026-10-16 (16 October 2026). Threshold counts are computed by this site.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).

San Francisco Threshold Days by Year

Key Facts for San Francisco Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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