Weather & Climate in Mill Valley, CA

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

Mill Valley enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 49°F in January while summers reach 68°F in July / relatively mild seasonal variation. The area gets 305 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 44.4 inches. Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 130 feet.

Temperature

49°F Jan (10°C) 68°F Jul (20°C)

Annual Average	59.3°F
	10% above US avg
January Average	49°F (10°C)
July Average	68°F (20°C)
Sunny Days	305 days/yr

Geography

Elevation	130 ft (40 m)
Area	4.9 sq mi (12.6 km²)
Population Density	2,942/sq mi
Coordinates	37.9081°N, 122.5423°W
Timezone	America/Los_Angeles
County	San Mateo County County
Nearest Airport	Metro Oakland International (OAK) 22 miles away

Precipitation & Snow

Annual Rainfall 44.4"

17% above 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

4,720 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	40 km	11 km
Apr 18, 1990	5 km NNW of Aromas, California	M5.4	134 km	5 km
Apr 18, 1990	4 km E of Interlaken, California	M5.1	130 km	7 km
Jan 16, 1993	9 km E of Gilroy, California	M4.9	137 km	7 km
May 14, 2002	5 km SSW of Gilroy, California	M4.9	134 km	7 km
Apr 19, 1996	2 km E of Aromas, California	M4.9	140 km	5 km
Apr 18, 1990	4 km NNW of Aromas, California	M4.9	134 km	6 km
Sep 3, 2000	5 km WSW of Yountville, California	M4.9	54 km	9 km
Sep 4, 1995	13 km SW of Middletown, California	M4.8	88 km	7 km
May 12, 2006	7 km W of Cobb, California	M4.7	104 km	4 km
Apr 18, 1990	4 km N of Aromas, California	M4.7	135 km	4 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	95 km	8 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	101 km	9 km
Jan 2, 2025	4 km NW of Cobb, CA	M4.7	106 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	127 km	15 km
Jan 11, 2000	6 km N of Geyserville, California	M4.6	101 km	6 km
Feb 18, 2004	4 km WNW of Cobb, California	M4.6	105 km	3 km
Jan 12, 2014	8 km W of Cobb, California	M4.5	104 km	2 km
Sep 19, 2023	15 km SW of Westley, CA	M4.5	122 km	4 km

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

Tornado History

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

Date	Rating	Distance	Path	Fatalities
May 5, 1998	EF2	75 km	0.6 mi	0
Jun 1, 1958	EF2	56 km	15.0 mi	0
Jan 11, 1951	EF2	71 km	5.7 mi	0
Mar 18, 2011	EF1	62 km	0.1 mi	0
Jan 23, 2010	EF1	68 km	1.6 mi	0
Mar 20, 2005	EF1	31 km	3.0 mi	0
Jan 27, 2005	EF1	94 km	0.5 mi	0
Dec 5, 1998	EF1	62 km	1.5 mi	0
May 5, 1998	EF1	70 km	0.3 mi	0
Dec 23, 1996	EF1	51 km	6.0 mi	0
Feb 22, 1996	EF1	73 km	1.0 mi	0
Dec 2, 1992	EF1	60 km	1.0 mi	0
Dec 2, 1992	EF1	63 km	7.5 mi	0
Dec 2, 1992	EF1	75 km	3.0 mi	0
Feb 27, 1983	EF1	62 km	0.8 mi	0
Jan 14, 1980	EF1	75 km	0.3 mi	0
Nov 10, 1964	EF1	73 km	1.0 mi	0
Feb 17, 1959	EF1	92 km	0.5 mi	0
Apr 1, 1958	EF1	36 km	0.2 mi	0
Apr 27, 2016	EF0	77 km	0.2 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	45 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	113 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	50 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	23 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	97 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (120 km).

Name	Type	Elevation	Last Eruption	Distance
Clear Lake	Volcanic field	1,439 m (4,721 ft)	Unknown	120 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	83 km
2018	COUNTY	92,450	93 km
2020	CZU AUG LIGHTNING	85,894	90 km
2019	KINCADE	77,780	87 km
2015	VALLEY	77,507	98 km
2020	GLASS	68,020	72 km
2017	NUNS	56,883	49 km
2020	WALLBRIDGE	55,194	89 km
2017	ATLAS	51,664	57 km
2004	RUMSEY	39,335	97 km
2017	TUBBS	36,981	74 km
1988	MILLER	35,750	70 km
2024	CORRAL	16,138	100 km
2004	GEYSERS	12,075	93 km
2009	CORRAL	12,006	99 km
1995	VISION	11,931	32 km
2015	WRAGG	8,455	76 km
2009	LOCKHEED	8,287	96 km
2014	MONTICELLO	6,984	81 km
1984	SITE 300 3	6,911	98 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	49°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

Mill Valley 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").

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