Weather & Climate in Fairfield, CA

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

Fairfield enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 48°F in January while summers reach 71°F in July. The area gets 319 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 33.2 inches. Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 39 feet.

Temperature

48°F Jan (9°C) 71°F Jul (22°C)

Annual Average	58.6°F
	9% above US avg
January Average	48°F (9°C)
July Average	71°F (22°C)
Sunny Days	319 days/yr

Geography

Elevation	39 ft (12 m)
Area	41.6 sq mi (107.7 km²)
Population Density	2,885/sq mi
Coordinates	38.2621°N, 122.0324°W
Timezone	America/Los_Angeles
County	Napa County County
Nearest Airport	Sacramento International (SMF) 38 miles away

Precipitation & Snow

Annual Rainfall 33.2"

13% below US avg

Snowfall 0.8"

Wettest Month (Jan) 5.35"

Driest Month (Jul) 0.04"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively High
Risk Score	95.3 / 100
Social Vulnerability	38.5 / 100
Community Resilience	76.0 / 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	Very High
Cold Wave	No Rating
Landslide	Relatively High
Coastal Flood	Relatively Moderate
Tsunami	Very Low
Volcano	Very Low
Avalanche	Very Low

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

Earthquake History

4,281 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	25 km	11 km
Apr 18, 1990	4 km E of Interlaken, California	M5.1	148 km	7 km
Aug 10, 2016	20 km NNE of Upper Lake, California	M5.1	136 km	14 km
Jan 16, 1993	9 km E of Gilroy, California	M4.9	147 km	7 km
May 14, 2002	5 km SSW of Gilroy, California	M4.9	149 km	7 km
Sep 3, 2000	5 km WSW of Yountville, California	M4.9	36 km	9 km
Sep 4, 1995	13 km SW of Middletown, California	M4.8	78 km	7 km
May 12, 2006	7 km W of Cobb, California	M4.7	92 km	4 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	104 km	8 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	110 km	9 km
Jan 2, 2025	4 km NW of Cobb, CA	M4.7	90 km	1 km
Mar 24, 1991	1 km NNE of Interlaken, California	M4.6	147 km	15 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	95 km	6 km
Feb 18, 2004	4 km WNW of Cobb, California	M4.6	90 km	3 km
Jan 12, 2014	8 km W of Cobb, California	M4.5	92 km	2 km
Sep 19, 2023	15 km SW of Westley, CA	M4.5	112 km	4 km
Sep 25, 2012	3 km N of Talmage, California	M4.5	141 km	11 km
Aug 3, 2006	5 km W of Glen Ellen, California	M4.5	50 km	9 km
Jun 8, 2024	7 km NW of The Geysers, CA	M4.5	92 km	4 km

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

Tornado History

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

Date	Rating	Distance	Path	Fatalities
May 5, 1998	EF2	99 km	0.6 mi	0
Feb 7, 1978	EF2	70 km	1.9 mi	0
Jun 1, 1958	EF2	83 km	15.0 mi	0
Jan 11, 1951	EF2	100 km	5.7 mi	0
Dec 24, 2015	EF1	94 km	6.2 mi	0
Oct 22, 2012	EF1	96 km	2.0 mi	0
Mar 18, 2011	EF1	63 km	0.1 mi	0
Jan 23, 2010	EF1	45 km	1.6 mi	0
Mar 20, 2005	EF1	76 km	3.0 mi	0
Dec 5, 1998	EF1	62 km	1.5 mi	0
May 5, 1998	EF1	98 km	0.3 mi	0
Dec 23, 1996	EF1	78 km	6.0 mi	0
Feb 22, 1996	EF1	69 km	1.0 mi	0
Dec 2, 1992	EF1	76 km	3.0 mi	0
Dec 2, 1992	EF1	77 km	7.5 mi	0
Dec 2, 1992	EF1	71 km	1.0 mi	0
Apr 19, 1988	EF1	78 km	0.2 mi	0
Apr 19, 1988	EF1	88 km	1.0 mi	0
Mar 22, 1983	EF1	78 km	2.0 mi	0
Feb 27, 1983	EF1	62 km	0.8 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	63 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	137 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	88 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	75 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	119 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (102 km).

Name	Type	Elevation	Last Eruption	Distance
Clear Lake	Volcanic field	1,439 m (4,721 ft)	Unknown	102 km

Source: Smithsonian Institution Global Volcanism Program (GVP).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: SCU LIGHTNING COMPLEX (405,787 acres, 2020).

Year	Name	Acres Burned	Distance
2020	SCU LIGHTNING COMPLEX	405,787	97 km
2020	HENNESSEY	314,241	46 km
2015	ROCKY	96,125	81 km
2018	COUNTY	92,450	48 km
2019	KINCADE	77,780	79 km
2015	VALLEY	77,507	77 km
2020	GLASS	68,020	55 km
2017	NUNS	56,883	42 km
2020	WALLBRIDGE	55,194	94 km
2017	ATLAS	51,664	21 km
2004	RUMSEY	39,335	59 km
1999	SIXTEEN	37,162	65 km
2017	TUBBS	36,981	66 km
1988	MILLER	35,750	19 km
2017	POCKET	18,691	93 km
2012	SIXTEEN COMPLEX	18,191	87 km
2024	CORRAL	16,138	86 km
2006	ZAM ASSIST	14,404	56 km
2008	WALKER	12,441	97 km
2004	GEYSERS	12,075	81 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	48°F (9°C)	5.4 in	Wettest
February	51°F (11°C)	4.5 in
March	54°F (12°C)	3.5 in
April	58°F (15°C)	1.2 in
May	64°F (18°C)	0.6 in
June	69°F (21°C)	0.1 in
July	71°F (22°C)	0.0 in	Driest
August	72°F (22°C)	0.1 in	Warmest
September	70°F (21°C)	0.3 in
October	64°F (18°C)	1.3 in
November	54°F (12°C)	3.4 in
December	47°F (8°C)	3.7 in	Coldest

Fairfield has a seasonal temperature swing of 25°F / from 47°F in December to 72°F in August. Total annual precipitation is 24.1 inches, with January being the wettest month (5.4") and July the driest (0.0").

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