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Weather & Climate in Suisun City, CA

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

Suisun City enjoys a temperate climate with an average annual temperature of 62°F (17°C). Winters average 49°F in January while summers reach 74°F in July. 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 24.5 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 20 feet.

Temperature

49°F Jan (9°C) 74°F Jul (23°C)
Annual Average61.7°F
14% above US avg
January Average49°F (9°C)
July Average74°F (23°C)
Sunny Days326 days/yr

Geography

Elevation20 ft (6 m)
Area4.2 sq mi (10.8 km²)
Population Density7,283/sq mi
Coordinates38.2483°N, 122.0101°W
TimezoneAmerica/Los_Angeles
CountyNapa County County
Nearest AirportMetro Oakland International (OAK)
38 miles away

Precipitation & Snow

Annual Rainfall 24.5"
35% below US avg
Snowfall 0.0"
Wettest Month (Jan) 5.35"
Driest Month (Jul) 0.04"

Air Quality

AQI Median48.0
RatingGood

Natural Hazard Risk

Overall RiskRelatively High
Risk Score95.3 / 100
Social Vulnerability38.5 / 100
Community Resilience76.0 / 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

4,339 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 27 km 11 km
Apr 18, 1990 5 km NNW of Aromas, California M5.4 150 km 5 km
Apr 18, 1990 4 km E of Interlaken, California M5.1 146 km 7 km
Aug 10, 2016 20 km NNE of Upper Lake, California M5.1 138 km 14 km
Jan 16, 1993 9 km E of Gilroy, California M4.9 145 km 7 km
Sep 3, 2000 5 km WSW of Yountville, California M4.9 38 km 9 km
Apr 18, 1990 4 km NNW of Aromas, California M4.9 150 km 6 km
May 14, 2002 5 km SSW of Gilroy, California M4.9 147 km 7 km
Sep 4, 1995 13 km SW of Middletown, California M4.8 80 km 7 km
May 12, 2006 7 km W of Cobb, California M4.7 94 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 93 km 1 km
Mar 24, 1991 1 km NNE of Interlaken, California M4.6 145 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 98 km 6 km
Feb 18, 2004 4 km WNW of Cobb, California M4.6 93 km 3 km
Jan 12, 2014 8 km W of Cobb, California M4.5 94 km 2 km
Sep 19, 2023 15 km SW of Westley, CA M4.5 110 km 4 km
Sep 25, 2012 3 km N of Talmage, California M4.5 143 km 11 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 98 km 0.6 mi 0
Feb 7, 1978 EF2 70 km 1.9 mi 0
Jun 1, 1958 EF2 85 km 15.0 mi 0
Jan 11, 1951 EF2 98 km 5.7 mi 0
Dec 24, 2015 EF1 93 km 6.2 mi 0
Oct 22, 2012 EF1 96 km 2.0 mi 0
Mar 18, 2011 EF1 65 km 0.1 mi 0
Jan 23, 2010 EF1 43 km 1.6 mi 0
Mar 20, 2005 EF1 76 km 3.0 mi 0
Dec 5, 1998 EF1 64 km 1.5 mi 0
May 5, 1998 EF1 97 km 0.3 mi 0
Dec 23, 1996 EF1 80 km 6.0 mi 0
Feb 22, 1996 EF1 71 km 1.0 mi 0
Dec 2, 1992 EF1 78 km 3.0 mi 0
Dec 2, 1992 EF1 79 km 7.5 mi 0
Dec 2, 1992 EF1 74 km 1.0 mi 0
Apr 19, 1988 EF1 76 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 64 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 62 km
1989 N. CALIFORNIA Earthquake 1.0 m 62 135 km
1856 N. CALIFORNIA Eruption + Earthquake 0.6 m — 87 km
1906 N. CALIFORNIA Eruption + Earthquake 0.1 m — 75 km
1865 N. CALIFORNIA Eruption + Earthquake — — 117 km
Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (104 km).

Name Type Elevation Last Eruption Distance
Clear Lake Volcanic field 1,439 m (4,721 ft) Unknown 104 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 95 km
2020 HENNESSEY 314,241 48 km
2015 ROCKY 96,125 83 km
2018 COUNTY 92,450 50 km
2019 KINCADE 77,780 82 km
2015 VALLEY 77,507 80 km
2020 GLASS 68,020 58 km
2017 NUNS 56,883 44 km
2020 WALLBRIDGE 55,194 96 km
2017 ATLAS 51,664 24 km
2004 RUMSEY 39,335 61 km
1999 SIXTEEN 37,162 68 km
2017 TUBBS 36,981 68 km
1988 MILLER 35,750 22 km
2017 POCKET 18,691 96 km
2012 SIXTEEN COMPLEX 18,191 89 km
2024 CORRAL 16,138 84 km
2006 ZAM ASSIST 14,404 57 km
2008 WALKER 12,441 100 km
2004 GEYSERS 12,075 83 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month Avg Temperature Precipitation Summary
January 49°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 74°F (23°C) 0.0 in Warmest, Driest
August 72°F (22°C) 0.1 in
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

Suisun City has a seasonal temperature swing of 27°F / from 47°F in December to 74°F in July. 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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