Weather & Climate in Monte Rio, CA

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

Monte Rio experiences four distinct seasons with an average annual temperature of 54°F (12°C). Winters average 50°F in January while summers reach 57°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 28.9 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 32 feet.

Temperature

50°F Jan (10°C) 57°F Jul (14°C)

Annual Average	53.5°F
	1% below US avg
January Average	50°F (10°C)
July Average	57°F (14°C)
Sunny Days	326 days/yr

Geography

Elevation	32 ft (10 m)
Area	2.0 sq mi (5.1 km²)
Population Density	401/sq mi
Coordinates	38.4736°N, 123.0262°W
Timezone	America/Los_Angeles
County	Sonoma County County
Nearest Airport	Metro Oakland International (OAK) 68 miles away

Precipitation & Snow

Annual Rainfall 28.9"

24% below US avg

Wettest Month (Jan) 8.62"

Driest Month (Jul) 0.12"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively High
Risk Score	99.1 / 100
Social Vulnerability	29.8 / 100
Community Resilience	66.2 / 100

Hazard Breakdown

Tornado	Very Low
Earthquake	Relatively High
Wildfire	Relatively High
Flood	Relatively High
Hail	Very Low
Strong Wind	Very 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 Moderate
Tsunami	Very Low
Volcano	Relatively Low
Avalanche	Very Low

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

Earthquake History

3,941 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	69 km	11 km
Aug 10, 2016	20 km NNE of Upper Lake, California	M5.1	97 km	14 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	34 km	7 km
Apr 18, 2007	15 km N of Potter Valley, California	M4.8	110 km	5 km
May 12, 2006	7 km W of Cobb, California	M4.7	42 km	4 km
Jan 2, 2025	4 km NW of Cobb, CA	M4.7	48 km	1 km
Aug 18, 1999	0 km S of Bolinas, California	M4.6	70 km	8 km
Jan 11, 2000	6 km N of Geyserville, California	M4.6	34 km	6 km
Feb 18, 2004	4 km WNW of Cobb, California	M4.6	46 km	3 km
Jan 12, 2014	8 km W of Cobb, California	M4.5	42 km	2 km
Sep 25, 2012	3 km N of Talmage, California	M4.5	78 km	11 km
Aug 3, 2006	5 km W of Glen Ellen, California	M4.5	40 km	9 km
Jun 8, 2024	7 km NW of The Geysers, CA	M4.5	42 km	4 km
Sep 19, 1992	7 km NW of Cobb, California	M4.5	48 km	3 km
Apr 24, 2007	7 km WSW of Cobb, California	M4.5	41 km	2 km
Jun 3, 2023	2km NW of The Geysers, CA	M4.5	41 km	4 km
Mar 14, 2013	5 km W of Cobb, California	M4.4	43 km	1 km
Mar 1, 2011	8 km W of Cobb, California	M4.4	42 km	2 km
Apr 12, 2023	7km WNW of Cobb, CA	M4.4	45 km	2 km

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

Tornado History

22 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 1 injury.

Date	Rating	Distance	Path	Fatalities
Jun 1, 1958	EF2	22 km	15.0 mi	0
Mar 18, 2011	EF1	28 km	0.1 mi	0
Jan 27, 2005	EF1	18 km	0.5 mi	0
Dec 5, 1998	EF1	29 km	1.5 mi	0
Dec 23, 1996	EF1	26 km	6.0 mi	0
Feb 22, 1996	EF1	27 km	1.0 mi	0
Dec 2, 1992	EF1	20 km	3.0 mi	0
Dec 2, 1992	EF1	14 km	7.5 mi	0
Dec 2, 1992	EF1	19 km	1.0 mi	0
Feb 27, 1983	EF1	29 km	0.8 mi	0
Nov 10, 1964	EF1	21 km	1.0 mi	0
Feb 17, 1959	EF1	20 km	0.5 mi	0
Apr 27, 2016	EF0	79 km	0.2 mi	0
Apr 7, 2011	EF0	83 km	0.1 mi	0
Mar 20, 2005	EF0	98 km	1.2 mi	0
Jan 11, 2005	EF0	92 km	0.1 mi	0
Dec 29, 2004	EF0	29 km	0.2 mi	0
Dec 5, 1998	EF0	85 km	1.5 mi	0
May 12, 1998	EF0	93 km	0.2 mi	0
Dec 23, 1996	EF0	85 km	0.3 mi	0

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

Tsunami History

3 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	118 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	126 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	98 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (60 km).

Name	Type	Elevation	Last Eruption	Distance
Clear Lake	Volcanic field	1,439 m (4,721 ft)	Unknown	60 km

Source: Smithsonian Institution Global Volcanism Program (GVP).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: RANCH (427,048 acres, 2018).

Year	Name	Acres Burned	Distance
2018	RANCH	427,048	91 km
2020	HENNESSEY	314,241	67 km
2015	ROCKY	96,125	70 km
2018	COUNTY	92,450	79 km
1996	FORK	83,209	85 km
2019	KINCADE	77,780	31 km
2015	VALLEY	77,507	50 km
2020	GLASS	68,020	43 km
2017	NUNS	56,883	48 km
2020	WALLBRIDGE	55,194	16 km
2017	ATLAS	51,664	70 km
2018	RIVER	48,920	65 km
2004	RUMSEY	39,335	73 km
1999	SIXTEEN	37,162	71 km
2017	TUBBS	36,981	32 km
2017	REDWOOD VALLEY INCIDENT	36,545	98 km
1988	MILLER	35,750	81 km
2017	POCKET	18,691	35 km
2012	SIXTEEN COMPLEX	18,191	86 km
2008	WALKER	12,441	81 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	50°F (10°C)	8.6 in	Wettest
February	50°F (10°C)	6.7 in
March	51°F (11°C)	6.1 in
April	53°F (12°C)	2.4 in
May	56°F (13°C)	0.8 in
June	60°F (15°C)	0.2 in
July	57°F (14°C)	0.1 in	Driest
August	62°F (17°C)	0.2 in	Warmest
September	62°F (17°C)	0.6 in
October	59°F (15°C)	2.6 in
November	53°F (12°C)	6.4 in
December	48°F (9°C)	6.9 in	Coldest

Monte Rio has a seasonal temperature swing of 14°F / from 48°F in December to 62°F in August. Total annual precipitation is 41.8 inches, with January being the wettest month (8.6") and July the driest (0.1").

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