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Weather & Climate in Mountain House, CA

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

Mountain House enjoys a temperate climate with an average annual temperature of 64°F (18°C). Winters average 48°F in January while summers reach 78°F in July. The area gets 330 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 12.4 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 85 feet.

Temperature

48°F Jan (9°C) 78°F Jul (25°C)
Annual Average63.5°F
18% above US avg
January Average48°F (9°C)
July Average78°F (25°C)
Sunny Days330 days/yr

Geography

Elevation85 ft (26 m)
Area4.6 sq mi (11.8 km²)
Population Density5,506/sq mi
Coordinates37.7673°N, 121.5449°W
TimezoneAmerica/Los_Angeles
CountySan Joaquin County County
Nearest AirportNorman Y Mineta San Jose International (SJC)
35 miles away

Precipitation & Snow

Annual Rainfall 12.4"
67% below US avg
Snowfall 0.0"
Wettest Month (Jan) 2.83"
Driest Month (Jul) 0.04"

Air Quality

AQI Median48.0
RatingGood

Natural Hazard Risk

Overall RiskRelatively High
Risk Score98.6 / 100
Social Vulnerability39.7 / 100
Community Resilience47.0 / 100

Hazard Breakdown

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

Earthquake History

4,136 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 84 km 11 km
Apr 18, 1990 5 km NNW of Aromas, California M5.4 93 km 5 km
Apr 18, 1990 4 km E of Interlaken, California M5.1 91 km 7 km
Aug 12, 1998 10 km SW of Ridgemark, California M5.1 113 km 9 km
Jan 16, 1993 9 km E of Gilroy, California M4.9 84 km 7 km
May 14, 2002 5 km SSW of Gilroy, California M4.9 89 km 7 km
Sep 3, 2000 5 km WSW of Yountville, California M4.9 102 km 9 km
Apr 19, 1996 2 km E of Aromas, California M4.9 98 km 5 km
Apr 18, 1990 4 km NNW of Aromas, California M4.9 94 km 6 km
Apr 23, 1995 22 km NNE of Soledad, California M4.9 133 km 7 km
Sep 4, 1995 13 km SW of Middletown, California M4.8 146 km 7 km
Apr 18, 1990 4 km N of Aromas, California M4.7 94 km 4 km
May 21, 1996 8 km ESE of East Foothills, California M4.7 48 km 8 km
Aug 11, 1993 14 km ESE of Alum Rock, California M4.7 52 km 9 km
Aug 27, 2011 21 km NE of Soledad, California M4.6 135 km 8 km
Mar 24, 1991 1 km NNE of Interlaken, California M4.6 91 km 15 km
Aug 18, 1999 0 km S of Bolinas, California M4.6 102 km 8 km
Sep 19, 2023 15 km SW of Westley, CA M4.5 43 km 4 km
Aug 3, 2006 5 km W of Glen Ellen, California M4.5 113 km 9 km
Jan 12, 2011 9 km SSE of San Juan Bautista, California M4.5 111 km 8 km
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

83 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 10 injuries.

Date Rating Distance Path Fatalities
May 5, 1998 EF2 62 km 0.6 mi 0
Apr 27, 1953 EF2 50 km 0.1 mi 0
Jan 11, 1951 EF2 67 km 5.7 mi 0
Dec 14, 2024 EF1 91 km 0.3 mi 0
Mar 11, 2023 EF1 91 km 0.8 mi 0
Jan 10, 2023 EF1 77 km 0.4 mi 0
Nov 15, 2015 EF1 70 km 3.0 mi 0
Jan 23, 2010 EF1 25 km 1.6 mi 0
Apr 14, 2006 EF1 50 km 0.5 mi 0
Mar 20, 2005 EF1 78 km 3.0 mi 0
Dec 20, 2001 EF1 91 km 0.5 mi 0
May 5, 1998 EF1 67 km 0.3 mi 0
Dec 12, 1996 EF1 61 km 0.6 mi 0
Apr 19, 1988 EF1 57 km 0.2 mi 0
Jan 14, 1980 EF1 44 km 0.3 mi 0
Mar 4, 1978 EF1 72 km 1.0 mi 0
Mar 4, 1978 EF1 65 km 2.5 mi 0
Mar 1, 1978 EF1 55 km 1.5 mi 0
May 31, 1967 EF1 31 km 0.1 mi 0
Apr 1, 1965 EF1 90 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 49 km
1989 N. CALIFORNIA Earthquake 1.0 m 62 87 km
1856 N. CALIFORNIA Eruption + Earthquake 0.6 m — 73 km
1906 N. CALIFORNIA Eruption + Earthquake 0.1 m — 84 km
1865 N. CALIFORNIA Eruption + Earthquake — — 70 km
Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (171 km).

Name Type Elevation Last Eruption Distance
Clear Lake Volcanic field 1,439 m (4,721 ft) Unknown 171 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 31 km
2020 CZU AUG LIGHTNING 85,894 91 km
2017 ATLAS 51,664 90 km
2007 LICK 47,424 61 km
2006 CANYON 36,851 49 km
1988 MILLER 35,750 88 km
2003 ANNIE 17,383 65 km
2024 CORRAL 16,138 16 km
2018 WAVERLY 12,238 67 km
2009 CORRAL 12,006 20 km
1985 LEXINGTON 11,550 76 km
1996 SCOTT 8,828 99 km
2015 WRAGG 8,455 92 km
2009 LOCKHEED 8,287 96 km
2003 BIRD 7,727 30 km
2014 MONTICELLO 6,984 97 km
1984 SITE 300 3 6,911 14 km
2005 TESLA 6,638 12 km
2003 DEL PUERTO 6,441 39 km
2016 COLD 6,289 97 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month Avg Temperature Precipitation Summary
January 48°F (9°C) 2.8 in Wettest
February 51°F (10°C) 2.4 in
March 54°F (12°C) 2.1 in
April 58°F (15°C) 0.9 in
May 64°F (18°C) 0.3 in
June 70°F (21°C) 0.1 in
July 78°F (25°C) 0.0 in Warmest, Driest
August 75°F (24°C) 0.1 in
September 72°F (22°C) 0.3 in
October 65°F (18°C) 0.9 in
November 54°F (12°C) 2.1 in
December 47°F (8°C) 2.1 in Coldest

Mountain House has a seasonal temperature swing of 31°F / from 47°F in December to 78°F in July. Total annual precipitation is 14.1 inches, with January being the wettest month (2.8") and July the driest (0.0").

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