Weather & Climate in Nicasio, CA

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

Nicasio enjoys a temperate climate with an average annual temperature of 58°F (14°C). Winters average 48°F in January while summers reach 67°F in July / relatively mild seasonal variation. The area gets 326 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 25.6 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 194 feet.

Temperature

48°F Jan (9°C) 67°F Jul (19°C)

Annual Average	58.0°F
	7% above US avg
January Average	48°F (9°C)
July Average	67°F (19°C)
Sunny Days	326 days/yr

Geography

Elevation	194 ft (59 m)
Area	1.3 sq mi (3.4 km²)
Population Density	86/sq mi
Coordinates	38.0606°N, 122.7008°W
Timezone	America/Los_Angeles
County	Marin County County
Nearest Airport	Metro Oakland International (OAK) 35 miles away

Precipitation & Snow

Annual Rainfall 25.6"

33% below US avg

Snowfall 0.0"

Wettest Month (Jan) 8.66"

Driest Month (Jul) 0.08"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively High
Risk Score	96.4 / 100
Social Vulnerability	24.7 / 100
Community Resilience	99.2 / 100

Hazard Breakdown

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

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

Earthquake History

4,155 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	38 km	11 km
Aug 10, 2016	20 km NNE of Upper Lake, California	M5.1	141 km	14 km
Sep 3, 2000	5 km WSW of Yountville, California	M4.9	43 km	9 km
Sep 4, 1995	13 km SW of Middletown, California	M4.8	69 km	7 km
May 12, 2006	7 km W of Cobb, California	M4.7	85 km	4 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	116 km	8 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	123 km	9 km
Jan 2, 2025	4 km NW of Cobb, CA	M4.7	87 km	1 km
Aug 18, 1999	0 km S of Bolinas, California	M4.6	17 km	8 km
Mar 24, 1991	1 km NNE of Interlaken, California	M4.6	149 km	15 km
Jan 11, 2000	6 km N of Geyserville, California	M4.6	81 km	6 km
Feb 18, 2004	4 km WNW of Cobb, California	M4.6	87 km	3 km
Jan 12, 2014	8 km W of Cobb, California	M4.5	84 km	2 km
Sep 19, 2023	15 km SW of Westley, CA	M4.5	142 km	4 km
Sep 25, 2012	3 km N of Talmage, California	M4.5	130 km	11 km
Aug 3, 2006	5 km W of Glen Ellen, California	M4.5	35 km	9 km
Jun 8, 2024	7 km NW of The Geysers, CA	M4.5	84 km	4 km
Sep 19, 1992	7 km NW of Cobb, California	M4.5	89 km	3 km
Apr 24, 2007	7 km WSW of Cobb, California	M4.5	82 km	2 km
Jun 3, 2023	2km NW of The Geysers, CA	M4.5	82 km	4 km

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

Tornado History

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

Date	Rating	Distance	Path	Fatalities
May 5, 1998	EF2	97 km	0.6 mi	0
Jun 1, 1958	EF2	35 km	15.0 mi	0
Jan 11, 1951	EF2	92 km	5.7 mi	0
Mar 18, 2011	EF1	44 km	0.1 mi	0
Jan 23, 2010	EF1	84 km	1.6 mi	0
Mar 20, 2005	EF1	52 km	3.0 mi	0
Jan 27, 2005	EF1	72 km	0.5 mi	0
Dec 5, 1998	EF1	43 km	1.5 mi	0
May 5, 1998	EF1	91 km	0.3 mi	0
Dec 23, 1996	EF1	29 km	6.0 mi	0
Feb 22, 1996	EF1	55 km	1.0 mi	0
Dec 2, 1992	EF1	55 km	3.0 mi	0
Dec 2, 1992	EF1	39 km	1.0 mi	0
Dec 2, 1992	EF1	42 km	7.5 mi	0
Feb 27, 1983	EF1	43 km	0.8 mi	0
Jan 14, 1980	EF1	97 km	0.3 mi	0
Nov 10, 1964	EF1	53 km	1.0 mi	0
Feb 17, 1959	EF1	70 km	0.5 mi	0
Apr 1, 1958	EF1	58 km	0.2 mi	0
Apr 27, 2016	EF0	72 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	66 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	135 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	72 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	44 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	119 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (101 km).

Name	Type	Elevation	Last Eruption	Distance
Clear Lake	Volcanic field	1,439 m (4,721 ft)	Unknown	101 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	72 km
2015	ROCKY	96,125	97 km
2018	COUNTY	92,450	84 km
2019	KINCADE	77,780	68 km
2015	VALLEY	77,507	81 km
2020	GLASS	68,020	56 km
2017	NUNS	56,883	36 km
2020	WALLBRIDGE	55,194	68 km
2017	ATLAS	51,664	53 km
2004	RUMSEY	39,335	86 km
1999	SIXTEEN	37,162	89 km
2017	TUBBS	36,981	56 km
1988	MILLER	35,750	67 km
2017	POCKET	18,691	81 km
2004	GEYSERS	12,075	74 km
1995	VISION	11,931	14 km
1985	UNNAMED	9,655	90 km
2015	WRAGG	8,455	72 km
2014	MONTICELLO	6,984	77 km
2016	COLD	6,289	76 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	48°F (9°C)	8.7 in	Coldest, Wettest
February	51°F (11°C)	7.2 in
March	52°F (11°C)	6.0 in
April	55°F (13°C)	2.4 in
May	58°F (14°C)	0.9 in
June	61°F (16°C)	0.2 in
July	67°F (19°C)	0.1 in	Warmest, Driest
August	65°F (18°C)	0.2 in
September	65°F (18°C)	0.5 in
October	61°F (16°C)	2.3 in
November	54°F (12°C)	6.1 in
December	49°F (9°C)	7.2 in

Nicasio has a seasonal temperature swing of 18°F / from 48°F in January to 67°F in July. Total annual precipitation is 41.7 inches, with January being the wettest month (8.7") and July the driest (0.1").

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