Weather & Climate in San Anselmo, CA

Temperature, precipitation, air quality, natural hazards, and monthly weather data.

San Anselmo enjoys a temperate climate with an average annual temperature of 60°F (15°C). Winters average 50°F in January while summers reach 68°F in July / relatively mild seasonal variation. The area gets 317 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 34.5 inches. Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 83 feet.

Temperature

50°F Jan (10°C) 68°F Jul (20°C)

Annual Average	59.5°F
	10% above US avg
January Average	50°F (10°C)
July Average	68°F (20°C)
Sunny Days	317 days/yr

Geography

Elevation	83 ft (25 m)
Area	2.7 sq mi (6.9 km²)
Population Density	4,743/sq mi
Coordinates	37.9821°N, 122.5699°W
Timezone	America/Los_Angeles
County	San Mateo County County
Nearest Airport	Metro Oakland International (OAK) 26 miles away

Precipitation & Snow

Annual Rainfall 34.5"

9% below US avg

Snowfall 0.0"

Wettest Month (Jan) 9.02"

Driest Month (Jul) 0.08"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively High
Risk Score	99.2 / 100
Social Vulnerability	20.5 / 100
Community Resilience	97.6 / 100

Hazard Breakdown

Tornado	Relatively Low
Earthquake	Relatively High
Wildfire	Relatively Moderate
Flood	Relatively High
Hail	Very Low
Strong Wind	Relatively Low
Heat Wave	Relatively Moderate
Winter Weather	Very Low
Lightning	Relatively Moderate
Drought	Relatively High
Cold Wave	No Rating
Landslide	Relatively High
Coastal Flood	Relatively High
Tsunami	Relatively Moderate

Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

4,454 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M6.0.

Aug 24, 2014	The 2014 South Napa, California Earthquake	M6.0	34 km	11 km
Apr 18, 1990	5 km NNW of Aromas, California	M5.4	142 km	5 km
Apr 18, 1990	4 km E of Interlaken, California	M5.1	138 km	7 km
Jan 16, 1993	9 km E of Gilroy, California	M4.9	145 km	7 km
Apr 18, 1990	4 km NNW of Aromas, California	M4.9	142 km	6 km
Sep 3, 2000	5 km WSW of Yountville, California	M4.9	46 km	9 km
May 14, 2002	5 km SSW of Gilroy, California	M4.9	142 km	7 km
Apr 19, 1996	2 km E of Aromas, California	M4.9	148 km	5 km
Sep 4, 1995	13 km SW of Middletown, California	M4.8	79 km	7 km
May 12, 2006	7 km W of Cobb, California	M4.7	95 km	4 km
Apr 18, 1990	4 km N of Aromas, California	M4.7	143 km	4 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	102 km	8 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	108 km	9 km
Jan 2, 2025	4 km NW of Cobb, CA	M4.7	97 km	1 km
Aug 18, 1999	0 km S of Bolinas, California	M4.6	13 km	8 km
Mar 24, 1991	1 km NNE of Interlaken, California	M4.6	135 km	15 km
Jan 11, 2000	6 km N of Geyserville, California	M4.6	93 km	6 km
Feb 18, 2004	4 km WNW of Cobb, California	M4.6	97 km	3 km
Jan 12, 2014	8 km W of Cobb, California	M4.5	95 km	2 km
Sep 19, 2023	15 km SW of Westley, CA	M4.5	127 km	4 km

Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

39 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 4 injuries.

Date	Rating	Distance	Path	Fatalities
May 5, 1998	EF2	83 km	0.6 mi	0
Jun 1, 1958	EF2	49 km	15.0 mi	0
Jan 11, 1951	EF2	79 km	5.7 mi	0
Mar 18, 2011	EF1	54 km	0.1 mi	0
Jan 23, 2010	EF1	71 km	1.6 mi	0
Mar 20, 2005	EF1	39 km	3.0 mi	0
Jan 27, 2005	EF1	86 km	0.5 mi	0
Dec 5, 1998	EF1	53 km	1.5 mi	0
May 5, 1998	EF1	78 km	0.3 mi	0
Dec 23, 1996	EF1	43 km	6.0 mi	0
Feb 22, 1996	EF1	65 km	1.0 mi	0
Dec 2, 1992	EF1	52 km	1.0 mi	0
Dec 2, 1992	EF1	55 km	7.5 mi	0
Dec 2, 1992	EF1	67 km	3.0 mi	0
Feb 27, 1983	EF1	53 km	0.8 mi	0
Jan 14, 1980	EF1	83 km	0.3 mi	0
Nov 10, 1964	EF1	64 km	1.0 mi	0
Feb 17, 1959	EF1	84 km	0.5 mi	0
Apr 1, 1958	EF1	45 km	0.2 mi	0
Sep 28, 2019	EF0	98 km	1.7 mi	0

Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).

Tsunami History

5 tsunamis recorded within 500 km. Highest wave on record: 4.5 m (15 ft).

Year	Location	Cause	Max Wave	Deaths	Distance
1868	N. CALIFORNIA	Eruption + Earthquake	4.5 m	30	52 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	121 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	59 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	32 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	105 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (111 km).

Name	Type	Elevation	Last Eruption	Distance
Clear Lake	Volcanic field	1,439 m (4,721 ft)	Unknown	111 km

Source: Smithsonian Institution Global Volcanism Program (GVP).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: HENNESSEY (314,241 acres, 2020).

Year	Name	Acres Burned	Distance
2020	HENNESSEY	314,241	76 km
2018	COUNTY	92,450	86 km
2020	CZU AUG LIGHTNING	85,894	98 km
2019	KINCADE	77,780	79 km
2015	VALLEY	77,507	90 km
2020	GLASS	68,020	63 km
2017	NUNS	56,883	41 km
2020	WALLBRIDGE	55,194	81 km
2017	ATLAS	51,664	52 km
2004	RUMSEY	39,335	90 km
1999	SIXTEEN	37,162	94 km
2017	TUBBS	36,981	66 km
1988	MILLER	35,750	65 km
2017	POCKET	18,691	92 km
2004	GEYSERS	12,075	85 km
1995	VISION	11,931	27 km
2015	WRAGG	8,455	71 km
2014	MONTICELLO	6,984	76 km
2005	TESLA	6,638	95 km
2016	COLD	6,289	75 km

Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	50°F (10°C)	9.0 in	Wettest
February	51°F (11°C)	7.5 in
March	53°F (11°C)	6.3 in
April	55°F (13°C)	2.6 in
May	58°F (15°C)	0.8 in
June	62°F (16°C)	0.2 in
July	68°F (20°C)	0.1 in	Warmest, Driest
August	65°F (18°C)	0.2 in
September	65°F (18°C)	0.4 in
October	62°F (16°C)	2.2 in
November	54°F (12°C)	6.3 in
December	49°F (10°C)	7.6 in	Coldest

San Anselmo has a seasonal temperature swing of 19°F / from 49°F in December to 68°F in July. Total annual precipitation is 43.3 inches, with January being the wettest month (9.0") and July the driest (0.1").

View full profile of San Anselmo, CA →