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Weather & Climate in Diablo, CA

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

Diablo 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 661 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

Elevation661 ft (201 m)
Area1.4 sq mi (3.5 km²)
Population Density788/sq mi
Coordinates37.8408°N, 121.9565°W
TimezoneAmerica/Los_Angeles
CountyContra Costa County County
Nearest AirportMetro Oakland International (OAK)
17 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

5,651 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 52 km 11 km
Apr 18, 1990 5 km NNW of Aromas, California M5.4 104 km 5 km
Aug 12, 1998 10 km SW of Ridgemark, California M5.1 129 km 9 km
Apr 18, 1990 4 km E of Interlaken, California M5.1 101 km 7 km
Jan 16, 1993 9 km E of Gilroy, California M4.9 101 km 7 km
Apr 18, 1990 4 km NNW of Aromas, California M4.9 105 km 6 km
May 14, 2002 5 km SSW of Gilroy, California M4.9 102 km 7 km
Apr 19, 1996 2 km E of Aromas, California M4.9 111 km 5 km
Sep 3, 2000 5 km WSW of Yountville, California M4.9 72 km 9 km
Sep 4, 1995 13 km SW of Middletown, California M4.8 116 km 7 km
May 12, 2006 7 km W of Cobb, California M4.7 132 km 4 km
May 21, 1996 8 km ESE of East Foothills, California M4.7 57 km 8 km
Apr 18, 1990 4 km N of Aromas, California M4.7 105 km 4 km
Aug 11, 1993 14 km ESE of Alum Rock, California M4.7 64 km 9 km
Jan 2, 2025 4 km NW of Cobb, CA M4.7 132 km 1 km
Mar 24, 1991 1 km NNE of Interlaken, California M4.6 100 km 15 km
Aug 18, 1999 0 km S of Bolinas, California M4.6 65 km 8 km
Jan 11, 2000 6 km N of Geyserville, California M4.6 133 km 6 km
Feb 18, 2004 4 km WNW of Cobb, California M4.6 131 km 3 km
Jan 12, 2014 8 km W of Cobb, California M4.5 132 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 53 km 0.6 mi 0
Apr 27, 1953 EF2 87 km 0.1 mi 0
Jan 11, 1951 EF2 54 km 5.7 mi 0
Dec 14, 2024 EF1 88 km 0.3 mi 0
Mar 18, 2011 EF1 95 km 0.1 mi 0
Jan 23, 2010 EF1 19 km 1.6 mi 0
Apr 14, 2006 EF1 87 km 0.5 mi 0
Mar 20, 2005 EF1 46 km 3.0 mi 0
Dec 20, 2001 EF1 98 km 0.5 mi 0
Dec 5, 1998 EF1 94 km 1.5 mi 0
May 5, 1998 EF1 53 km 0.3 mi 0
Dec 23, 1996 EF1 97 km 6.0 mi 0
Dec 12, 1996 EF1 98 km 0.6 mi 0
Dec 2, 1992 EF1 99 km 1.0 mi 0
Apr 19, 1988 EF1 80 km 0.2 mi 0
Feb 27, 1983 EF1 94 km 0.8 mi 0
Jan 14, 1980 EF1 41 km 0.3 mi 0
Mar 1, 1978 EF1 92 km 1.5 mi 0
May 31, 1967 EF1 59 km 0.1 mi 0
Apr 1, 1965 EF1 97 km 0.1 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 20 km
1989 N. CALIFORNIA Earthquake 1.0 m 62 90 km
1856 N. CALIFORNIA Eruption + Earthquake 0.6 m — 49 km
1906 N. CALIFORNIA Eruption + Earthquake 0.1 m — 50 km
1865 N. CALIFORNIA Eruption + Earthquake — — 71 km
Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (144 km).

Name Type Elevation Last Eruption Distance
Clear Lake Volcanic field 1,439 m (4,721 ft) Unknown 144 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 56 km
2020 HENNESSEY 314,241 92 km
2018 COUNTY 92,450 95 km
2020 CZU AUG LIGHTNING 85,894 81 km
2020 GLASS 68,020 95 km
2017 NUNS 56,883 74 km
2017 ATLAS 51,664 63 km
2007 LICK 47,424 83 km
2006 CANYON 36,851 76 km
1988 MILLER 35,750 67 km
2003 ANNIE 17,383 93 km
2024 CORRAL 16,138 49 km
2018 WAVERLY 12,238 99 km
2009 CORRAL 12,006 50 km
1995 VISION 11,931 83 km
1985 LEXINGTON 11,550 77 km
2015 WRAGG 8,455 72 km
2009 LOCKHEED 8,287 87 km
2003 BIRD 7,727 64 km
2014 MONTICELLO 6,984 78 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

Diablo 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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