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Weather & Climate in Clayton, CA

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

Clayton enjoys a temperate climate with an average annual temperature of 58°F (15°C). Winters average 48°F in January while summers reach 72°F in July. The area gets 323 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 26.1 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 446 feet.

Temperature

48°F Jan (9°C) 72°F Jul (22°C)
Annual Average58.4°F
8% above US avg
January Average48°F (9°C)
July Average72°F (22°C)
Sunny Days323 days/yr

Geography

Elevation446 ft (136 m)
Area3.8 sq mi (9.9 km²)
Population Density2,855/sq mi
Coordinates37.9403°N, 121.9301°W
TimezoneAmerica/Los_Angeles
CountyContra Costa County County
Nearest AirportMetro Oakland International (OAK)
22 miles away

Precipitation & Snow

Annual Rainfall 26.1"
31% below US avg
Snowfall 0.7"
Wettest Month (Jan) 4.88"
Driest Month (Jul) 0.04"

Air Quality

AQI Median48.0
RatingGood

Natural Hazard Risk

Overall RiskVery High
Risk Score99.5 / 100
Social Vulnerability21.5 / 100
Community Resilience67.8 / 100

Hazard Breakdown

Tornado Relatively Low
Earthquake Relatively High
Wildfire Relatively Moderate
Flood Very High
Hail Very Low
Strong Wind Relatively Low
Heat Wave Relatively High
Winter Weather Very Low
Lightning Relatively High
Drought Relatively High
Cold Wave No Rating
Landslide Relatively High
Coastal Flood Relatively Moderate
Tsunami Relatively Low
Volcano Very Low
Avalanche Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

5,288 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 45 km 11 km
Apr 18, 1990 5 km NNW of Aromas, California M5.4 115 km 5 km
Aug 12, 1998 10 km SW of Ridgemark, California M5.1 138 km 9 km
Apr 18, 1990 4 km E of Interlaken, California M5.1 111 km 7 km
Jan 16, 1993 9 km E of Gilroy, California M4.9 111 km 7 km
Apr 19, 1996 2 km E of Aromas, California M4.9 121 km 5 km
May 14, 2002 5 km SSW of Gilroy, California M4.9 112 km 7 km
Sep 3, 2000 5 km WSW of Yountville, California M4.9 65 km 9 km
Apr 18, 1990 4 km NNW of Aromas, California M4.9 115 km 6 km
Sep 4, 1995 13 km SW of Middletown, California M4.8 109 km 7 km
May 12, 2006 7 km W of Cobb, California M4.7 124 km 4 km
May 21, 1996 8 km ESE of East Foothills, California M4.7 67 km 8 km
Apr 18, 1990 4 km N of Aromas, California M4.7 115 km 4 km
Aug 11, 1993 14 km ESE of Alum Rock, California M4.7 73 km 9 km
Jan 2, 2025 4 km NW of Cobb, CA M4.7 124 km 1 km
Mar 24, 1991 1 km NNE of Interlaken, California M4.6 110 km 15 km
Aug 18, 1999 0 km S of Bolinas, California M4.6 67 km 8 km
Jan 11, 2000 6 km N of Geyserville, California M4.6 126 km 6 km
Feb 18, 2004 4 km WNW of Cobb, California M4.6 124 km 3 km
Jan 12, 2014 8 km W of Cobb, California M4.5 124 km 2 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

75 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 9 injuries.

Date Rating Distance Path Fatalities
May 5, 1998 EF2 64 km 0.6 mi 0
Feb 7, 1978 EF2 94 km 1.9 mi 0
Jun 1, 1958 EF2 99 km 15.0 mi 0
Apr 27, 1953 EF2 88 km 0.1 mi 0
Jan 11, 1951 EF2 66 km 5.7 mi 0
Dec 14, 2024 EF1 100 km 0.3 mi 0
Mar 18, 2011 EF1 89 km 0.1 mi 0
Jan 23, 2010 EF1 15 km 1.6 mi 0
Apr 14, 2006 EF1 88 km 0.5 mi 0
Mar 20, 2005 EF1 54 km 3.0 mi 0
Dec 5, 1998 EF1 88 km 1.5 mi 0
May 5, 1998 EF1 65 km 0.3 mi 0
Dec 23, 1996 EF1 94 km 6.0 mi 0
Dec 12, 1996 EF1 97 km 0.6 mi 0
Feb 22, 1996 EF1 97 km 1.0 mi 0
Dec 2, 1992 EF1 94 km 1.0 mi 0
Dec 2, 1992 EF1 99 km 7.5 mi 0
Apr 19, 1988 EF1 73 km 0.2 mi 0
Feb 27, 1983 EF1 88 km 0.8 mi 0
Jan 14, 1980 EF1 51 km 0.3 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 31 km
1989 N. CALIFORNIA Earthquake 1.0 m 62 101 km
1856 N. CALIFORNIA Eruption + Earthquake 0.6 m — 59 km
1906 N. CALIFORNIA Eruption + Earthquake 0.1 m — 57 km
1865 N. CALIFORNIA Eruption + Earthquake — — 82 km
Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (136 km).

Name Type Elevation Last Eruption Distance
Clear Lake Volcanic field 1,439 m (4,721 ft) Unknown 136 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 63 km
2020 HENNESSEY 314,241 82 km
2018 COUNTY 92,450 85 km
2020 CZU AUG LIGHTNING 85,894 92 km
2020 GLASS 68,020 87 km
2017 NUNS 56,883 68 km
2017 ATLAS 51,664 54 km
2007 LICK 47,424 91 km
2004 RUMSEY 39,335 96 km
2017 TUBBS 36,981 96 km
2006 CANYON 36,851 83 km
1988 MILLER 35,750 56 km
2003 ANNIE 17,383 99 km
2024 CORRAL 16,138 54 km
2006 ZAM ASSIST 14,404 91 km
2018 WAVERLY 12,238 95 km
2009 CORRAL 12,006 55 km
1995 VISION 11,931 83 km
1985 LEXINGTON 11,550 88 km
2015 WRAGG 8,455 61 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month Avg Temperature Precipitation Summary
January 48°F (9°C) 4.9 in Wettest
February 50°F (10°C) 4.0 in
March 52°F (11°C) 3.4 in
April 56°F (14°C) 1.4 in
May 62°F (16°C) 0.5 in
June 67°F (20°C) 0.2 in
July 72°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) 3.6 in Coldest

Clayton has a seasonal temperature swing of 25°F / from 47°F in December to 72°F in August. Total annual precipitation is 23.1 inches, with January being the wettest month (4.9") and July the driest (0.0").

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