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Weather & Climate in Belmont, CA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Belmont enjoys a temperate climate with an average annual temperature of 59°F (15°C). Winters average 51°F in January while summers reach 64°F in July / relatively mild seasonal variation. 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 19.6 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 195 feet.
Temperature
51°F Jan (11°C)
64°F Jul (18°C)
| Annual Average | 58.7°F |
| 9% above US avg | |
| January Average | 51°F (11°C) |
| July Average | 64°F (18°C) |
| Sunny Days | 330 days/yr |
Geography
| Elevation | 195 ft (59 m) |
| Area | 4.6 sq mi (12.0 km²) |
| Population Density | 5,941/sq mi |
| Coordinates | 37.5144°N, 122.2945°W |
| Timezone | America/Los_Angeles |
| County | San Mateo County County |
| Nearest Airport | San Francisco International (SFO) 8 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
4,850 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 | 78 km | 11 km |
| Apr 18, 1990 | 5 km NNW of Aromas, California | M5.4 | 86 km | 5 km |
| Aug 12, 1998 | 10 km SW of Ridgemark, California | M5.1 | 112 km | 9 km |
| Apr 18, 1990 | 4 km E of Interlaken, California | M5.1 | 82 km | 7 km |
| Jan 16, 1993 | 9 km E of Gilroy, California | M4.9 | 92 km | 7 km |
| Apr 18, 1990 | 4 km NNW of Aromas, California | M4.9 | 86 km | 6 km |
| Sep 3, 2000 | 5 km WSW of Yountville, California | M4.9 | 97 km | 9 km |
| Apr 19, 1996 | 2 km E of Aromas, California | M4.9 | 92 km | 5 km |
| May 14, 2002 | 5 km SSW of Gilroy, California | M4.9 | 87 km | 7 km |
| Apr 23, 1995 | 22 km NNE of Soledad, California | M4.9 | 140 km | 7 km |
| Sep 4, 1995 | 13 km SW of Middletown, California | M4.8 | 136 km | 7 km |
| May 21, 1996 | 8 km ESE of East Foothills, California | M4.7 | 53 km | 8 km |
| Apr 18, 1990 | 4 km N of Aromas, California | M4.7 | 87 km | 4 km |
| Aug 11, 1993 | 14 km ESE of Alum Rock, California | M4.7 | 59 km | 9 km |
| Aug 27, 2011 | 21 km NE of Soledad, California | M4.6 | 143 km | 8 km |
| Aug 18, 1999 | 0 km S of Bolinas, California | M4.6 | 56 km | 8 km |
| Mar 24, 1991 | 1 km NNE of Interlaken, California | M4.6 | 79 km | 15 km |
| Jan 11, 2000 | 6 km N of Geyserville, California | M4.6 | 150 km | 6 km |
| Sep 19, 2023 | 15 km SW of Westley, CA | M4.5 | 89 km | 4 km |
| Aug 3, 2006 | 5 km W of Glen Ellen, California | M4.5 | 98 km | 9 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
39 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 9 injuries.
| Date | Rating | Distance | Path | Fatalities |
| May 5, 1998 | EF2 | 28 km | 0.6 mi | 0 |
| Jan 11, 1951 | EF2 | 22 km | 5.7 mi | 0 |
| Dec 14, 2024 | EF1 | 57 km | 0.3 mi | 0 |
| Jan 23, 2010 | EF1 | 64 km | 1.6 mi | 0 |
| Mar 20, 2005 | EF1 | 19 km | 3.0 mi | 0 |
| Dec 20, 2001 | EF1 | 76 km | 0.5 mi | 0 |
| May 5, 1998 | EF1 | 22 km | 0.3 mi | 0 |
| Dec 23, 1996 | EF1 | 99 km | 6.0 mi | 0 |
| Jan 14, 1980 | EF1 | 37 km | 0.3 mi | 0 |
| Apr 1, 1965 | EF1 | 74 km | 0.1 mi | 0 |
| Apr 1, 1958 | EF1 | 13 km | 0.2 mi | 0 |
| Jan 6, 2019 | EF0 | 67 km | 0.5 mi | 0 |
| Jan 6, 2019 | EF0 | 66 km | 0.1 mi | 0 |
| Dec 22, 2012 | EF0 | 82 km | 1.1 mi | 0 |
| Apr 11, 2012 | EF0 | 94 km | 0.3 mi | 0 |
| Apr 7, 2011 | EF0 | 83 km | 0.1 mi | 0 |
| Apr 14, 2007 | EF0 | 84 km | 0.2 mi | 0 |
| Dec 26, 2005 | EF0 | 81 km | 0.3 mi | 0 |
| Apr 8, 2005 | EF0 | 94 km | 1.5 mi | 0 |
| Jan 11, 2005 | EF0 | 99 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 | 27 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 65 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | — | 2 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | — | 28 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | — | — | 49 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
1 volcano within 200 km. Closest: Clear Lake (167 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 167 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 | 70 km |
| 2020 | CZU AUG LIGHTNING | 85,894 | 42 km |
| 2017 | NUNS | 56,883 | 95 km |
| 2017 | ATLAS | 51,664 | 95 km |
| 2007 | LICK | 47,424 | 83 km |
| 2006 | CANYON | 36,851 | 86 km |
| 2003 | ANNIE | 17,383 | 98 km |
| 2024 | CORRAL | 16,138 | 75 km |
| 2009 | CORRAL | 12,006 | 72 km |
| 1995 | VISION | 11,931 | 77 km |
| 1985 | LEXINGTON | 11,550 | 53 km |
| 2009 | LOCKHEED | 8,287 | 49 km |
| 2003 | BIRD | 7,727 | 85 km |
| 1984 | SITE 300 3 | 6,911 | 74 km |
| 2005 | TESLA | 6,638 | 66 km |
| 2003 | DEL PUERTO | 6,441 | 79 km |
| 2006 | MIDWAY | 6,243 | 70 km |
| 2020 | CREWS | 5,802 | 92 km |
| 2003 | DEVIL | 4,975 | 64 km |
| 2020 | WOODWARD | 4,952 | 73 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 51°F (11°C) | 4.1 in | Wettest |
| February | 53°F (11°C) | 3.5 in | |
| March | 54°F (12°C) | 3.1 in | |
| April | 57°F (14°C) | 1.3 in | |
| May | 60°F (15°C) | 0.4 in | |
| June | 63°F (17°C) | 0.1 in | |
| July | 64°F (18°C) | 0.0 in | Driest |
| August | 66°F (19°C) | 0.1 in | Warmest |
| September | 65°F (18°C) | 0.2 in | |
| October | 61°F (16°C) | 1.2 in | |
| November | 55°F (13°C) | 2.9 in | |
| December | 49°F (10°C) | 3.0 in | Coldest |
Belmont has a seasonal temperature swing of 16°F / from 49°F in December to 66°F in August. Total annual precipitation is 19.8 inches, with January being the wettest month (4.1") and July the driest (0.0").