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Weather & Climate in San Bruno, CA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
San Bruno enjoys a temperate climate with an average annual temperature of 57°F (14°C). Winters average 52°F in January while summers reach 61°F in July / relatively mild seasonal variation. The area gets 317 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 31.9 inches. Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 371 feet.
Temperature
52°F Jan (11°C)
61°F Jul (16°C)
| Annual Average | 57.4°F |
| 6% above US avg | |
| January Average | 52°F (11°C) |
| July Average | 61°F (16°C) |
| Sunny Days | 317 days/yr |
Geography
| Elevation | 371 ft (113 m) |
| Area | 5.5 sq mi (14.1 km²) |
| Population Density | 7,762/sq mi |
| Coordinates | 37.6256°N, 122.4314°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 3 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 48.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 99.2 / 100 |
| Social Vulnerability | 20.5 / 100 |
| Community Resilience | 97.6 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Earthquake | Relatively High |
| Wildfire | Relatively Moderate |
| Flood | Relatively High |
| Hail | Very Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Moderate |
| Winter Weather | Very Low |
| Lightning | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | No Rating |
| Landslide | Relatively High |
| Coastal Flood | Relatively High |
| Tsunami | Relatively Moderate |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
5,495 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 | 66 km | 11 km |
| Apr 18, 1990 | 5 km NNW of Aromas, California | M5.4 | 103 km | 5 km |
| Aug 12, 1998 | 10 km SW of Ridgemark, California | M5.1 | 130 km | 9 km |
| Apr 18, 1990 | 4 km E of Interlaken, California | M5.1 | 99 km | 7 km |
| Jan 16, 1993 | 9 km E of Gilroy, California | M4.9 | 109 km | 7 km |
| Apr 19, 1996 | 2 km E of Aromas, California | M4.9 | 110 km | 5 km |
| May 14, 2002 | 5 km SSW of Gilroy, California | M4.9 | 104 km | 7 km |
| Sep 3, 2000 | 5 km WSW of Yountville, California | M4.9 | 84 km | 9 km |
| Apr 18, 1990 | 4 km NNW of Aromas, California | M4.9 | 103 km | 6 km |
| Sep 4, 1995 | 13 km SW of Middletown, California | M4.8 | 121 km | 7 km |
| May 12, 2006 | 7 km W of Cobb, California | M4.7 | 137 km | 4 km |
| May 21, 1996 | 8 km ESE of East Foothills, California | M4.7 | 69 km | 8 km |
| Apr 18, 1990 | 4 km N of Aromas, California | M4.7 | 104 km | 4 km |
| Aug 11, 1993 | 14 km ESE of Alum Rock, California | M4.7 | 75 km | 9 km |
| Jan 2, 2025 | 4 km NW of Cobb, CA | M4.7 | 139 km | 1 km |
| Mar 24, 1991 | 1 km NNE of Interlaken, California | M4.6 | 96 km | 15 km |
| Aug 18, 1999 | 0 km S of Bolinas, California | M4.6 | 39 km | 8 km |
| Jan 11, 2000 | 6 km N of Geyserville, California | M4.6 | 134 km | 6 km |
| Feb 18, 2004 | 4 km WNW of Cobb, California | M4.6 | 138 km | 3 km |
| Jan 12, 2014 | 8 km W of Cobb, California | M4.5 | 136 km | 2 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
41 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 9 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 5, 1998 | EF2 | 45 km | 0.6 mi | 0 |
| Jun 1, 1958 | EF2 | 87 km | 15.0 mi | 0 |
| Jan 11, 1951 | EF2 | 40 km | 5.7 mi | 0 |
| Dec 14, 2024 | EF1 | 73 km | 0.3 mi | 0 |
| Mar 18, 2011 | EF1 | 95 km | 0.1 mi | 0 |
| Jan 23, 2010 | EF1 | 67 km | 1.6 mi | 0 |
| Mar 20, 2005 | EF1 | 3 km | 3.0 mi | 0 |
| Dec 20, 2001 | EF1 | 93 km | 0.5 mi | 0 |
| Dec 5, 1998 | EF1 | 95 km | 1.5 mi | 0 |
| May 5, 1998 | EF1 | 39 km | 0.3 mi | 0 |
| Dec 23, 1996 | EF1 | 82 km | 6.0 mi | 0 |
| Dec 2, 1992 | EF1 | 95 km | 7.5 mi | 0 |
| Dec 2, 1992 | EF1 | 93 km | 1.0 mi | 0 |
| Feb 27, 1983 | EF1 | 95 km | 0.8 mi | 0 |
| Jan 14, 1980 | EF1 | 51 km | 0.3 mi | 0 |
| Apr 1, 1965 | EF1 | 91 km | 0.1 mi | 0 |
| Apr 1, 1958 | EF1 | 7 km | 0.2 mi | 0 |
| Jan 6, 2019 | EF0 | 83 km | 0.5 mi | 0 |
| Jan 6, 2019 | EF0 | 82 km | 0.1 mi | 0 |
| Dec 22, 2012 | EF0 | 99 km | 1.1 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 | 30 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 82 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | - | 18 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | - | 10 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 67 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (152 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 152 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 | 83 km |
| 2020 | CZU AUG LIGHTNING | 85,894 | 57 km |
| 2017 | NUNS | 56,883 | 81 km |
| 2017 | ATLAS | 51,664 | 84 km |
| 2007 | LICK | 47,424 | 99 km |
| 1988 | MILLER | 35,750 | 94 km |
| 2024 | CORRAL | 16,138 | 86 km |
| 2009 | CORRAL | 12,006 | 83 km |
| 1995 | VISION | 11,931 | 60 km |
| 1985 | LEXINGTON | 11,550 | 70 km |
| 2009 | LOCKHEED | 8,287 | 63 km |
| 2003 | BIRD | 7,727 | 97 km |
| 1984 | SITE 300 3 | 6,911 | 84 km |
| 2005 | TESLA | 6,638 | 76 km |
| 2003 | DEL PUERTO | 6,441 | 93 km |
| 2006 | MIDWAY | 6,243 | 80 km |
| 2003 | DEVIL | 4,975 | 77 km |
| 2020 | WOODWARD | 4,952 | 56 km |
| 2003 | JUMP | 4,817 | 85 km |
| 2016 | LOMA | 4,380 | 78 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 52°F (11°C) | 5.9 in | Wettest |
| February | 52°F (11°C) | 4.9 in | |
| March | 53°F (11°C) | 4.5 in | |
| April | 55°F (13°C) | 1.9 in | |
| May | 57°F (14°C) | 0.6 in | |
| June | 59°F (15°C) | 0.2 in | |
| July | 61°F (16°C) | 0.1 in | Driest |
| August | 62°F (17°C) | 0.1 in | |
| September | 63°F (17°C) | 0.4 in | Warmest |
| October | 60°F (16°C) | 1.7 in | |
| November | 54°F (12°C) | 4.1 in | |
| December | 50°F (10°C) | 4.6 in | Coldest |
San Bruno has a seasonal temperature swing of 13°F / from 50°F in December to 63°F in September. Total annual precipitation is 28.9 inches, with January being the wettest month (5.9") and July the driest (0.1").