Weather & Climate in Piedmont, CA

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

Piedmont enjoys a temperate climate with an average annual temperature of 58°F (15°C). Winters average 50°F in January while summers reach 64°F in July / relatively mild seasonal variation. Annual precipitation totals 18.7 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 27 / among the cleanest air in the country. 88% of days have good air quality. The city sits at an elevation of 333 feet.

Temperature

50°F Jan (10°C) 64°F Jul (18°C)
Annual Average58.1°F
8% above US avg
January Average50°F (10°C)
July Average64°F (18°C)

Geography

Elevation333 ft (101 m)
Area1.7 sq mi (4.4 km²)
Population Density6,478/sq mi
Coordinates37.8225°N, 122.2300°W
TimezoneAmerica/Los_Angeles
CountySan Mateo County County
Nearest AirportMetro Oakland International (OAK)
7 miles away

Precipitation & Snow

Annual Rainfall 18.7"
51% below US avg
Snowfall 0.0"
Wettest Month (Dec) 3.84"
Driest Month (Aug) 0.04"

Air Quality

AQI Median27.0
RatingGood
Good Days %88.1%
Unhealthy Days0

Natural Hazard Risk

Overall RiskRelatively High
Risk Score99.2 / 100
Social Vulnerability20.5 / 100
Community Resilience97.6 / 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

5,273 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 44 km 11 km
Apr 18, 1990 5 km NNW of Aromas, California M5.4 111 km 5 km
Aug 12, 1998 10 km SW of Ridgemark, California M5.1 137 km 9 km
Apr 18, 1990 4 km E of Interlaken, California M5.1 108 km 7 km
Jan 16, 1993 9 km E of Gilroy, California M4.9 112 km 7 km
Sep 3, 2000 5 km WSW of Yountville, California M4.9 64 km 9 km
Apr 19, 1996 2 km E of Aromas, California M4.9 118 km 5 km
Apr 18, 1990 4 km NNW of Aromas, California M4.9 111 km 6 km
May 14, 2002 5 km SSW of Gilroy, California M4.9 110 km 7 km
Sep 4, 1995 13 km SW of Middletown, California M4.8 106 km 7 km
May 12, 2006 7 km W of Cobb, California M4.7 122 km 4 km
May 21, 1996 8 km ESE of East Foothills, California M4.7 68 km 8 km
Apr 18, 1990 4 km N of Aromas, California M4.7 112 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 M4.7 123 km 1 km
Aug 18, 1999 0 km S of Bolinas, California M4.6 41 km 8 km
Mar 24, 1991 1 km NNE of Interlaken, California M4.6 105 km 15 km
Jan 11, 2000 6 km N of Geyserville, California M4.6 121 km 6 km
Feb 18, 2004 4 km WNW of Cobb, California M4.6 122 km 3 km
Jan 12, 2014 8 km W of Cobb, California M4.5 122 km 2 km
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.

Tornado History

60 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
Jun 1, 1958 EF2 83 km 15.0 mi 0
Jan 11, 1951 EF2 51 km 5.7 mi 0
Dec 14, 2024 EF1 88 km 0.3 mi 0
Mar 18, 2011 EF1 82 km 0.1 mi 0
Jan 23, 2010 EF1 42 km 1.6 mi 0
Mar 20, 2005 EF1 25 km 3.0 mi 0
Dec 5, 1998 EF1 81 km 1.5 mi 0
May 5, 1998 EF1 50 km 0.3 mi 0
Dec 23, 1996 EF1 78 km 6.0 mi 0
Feb 22, 1996 EF1 92 km 1.0 mi 0
Dec 2, 1992 EF1 87 km 7.5 mi 0
Dec 2, 1992 EF1 96 km 3.0 mi 0
Dec 2, 1992 EF1 83 km 1.0 mi 0
Feb 27, 1983 EF1 81 km 0.8 mi 0
Jan 14, 1980 EF1 49 km 0.3 mi 0
May 31, 1967 EF1 83 km 0.1 mi 0
Nov 10, 1964 EF1 93 km 1.0 mi 0
Apr 1, 1958 EF1 25 km 0.2 mi 0
Nov 8, 2022 EF0 98 km 0.8 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 18 km
1989 N. CALIFORNIA Earthquake 1.0 m 62 93 km
1856 N. CALIFORNIA Eruption + Earthquake 0.6 m - 36 km
1906 N. CALIFORNIA Eruption + Earthquake 0.1 m - 27 km
1865 N. CALIFORNIA Eruption + Earthquake - - 75 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 74 km
2020 HENNESSEY 314,241 89 km
2018 COUNTY 92,450 96 km
2020 CZU AUG LIGHTNING 85,894 75 km
2020 GLASS 68,020 86 km
2017 NUNS 56,883 63 km
2017 ATLAS 51,664 60 km
2007 LICK 47,424 97 km
2017 TUBBS 36,981 92 km
2006 CANYON 36,851 93 km
1988 MILLER 35,750 69 km
2024 CORRAL 16,138 71 km
2009 CORRAL 12,006 70 km
1995 VISION 11,931 61 km
1985 LEXINGTON 11,550 80 km
2015 WRAGG 8,455 75 km
2009 LOCKHEED 8,287 82 km
2003 BIRD 7,727 84 km
2014 MONTICELLO 6,984 81 km
1984 SITE 300 3 6,911 69 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month Avg Temperature Precipitation Summary
January 50°F (10°C) 3.4 in Coldest
February 53°F (11°C) 3.5 in
March 55°F (13°C) 2.7 in
April 57°F (14°C) 1.4 in
May 60°F (16°C) 0.6 in
June 63°F (17°C) 0.2 in
July 64°F (18°C) 0.0 in Driest
August 65°F (18°C) 0.0 in
September 65°F (18°C) 0.1 in Warmest
October 61°F (16°C) 0.9 in
November 55°F (13°C) 2.0 in
December 50°F (10°C) 3.8 in Wettest

Piedmont has a seasonal temperature swing of 15°F / from 50°F in January to 65°F in September. Total annual precipitation is 18.7 inches, with December being the wettest month (3.8") and July the driest (0.0").

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