Weather & Climate in San Ramon, CA

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

San Ramon enjoys a temperate climate with an average annual temperature of 57°F (14°C). Winters average 47°F in January while summers reach 68°F in July. The area gets 322 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 34.2 inches. The area receives 2.8 inches of snow annually. Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 650 feet.

Temperature

47°F Jan (8°C) 68°F Jul (20°C)

Annual Average	56.5°F
	5% above US avg
January Average	47°F (8°C)
July Average	68°F (20°C)
Sunny Days	322 days/yr

Geography

Elevation	650 ft (198 m)
Area	18.1 sq mi (46.8 km²)
Population Density	4,274/sq mi
Coordinates	37.7653°N, 121.9320°W
Timezone	America/Los_Angeles
County	Alameda County County
Nearest Airport	Metro Oakland International (OAK) 16 miles away

Precipitation & Snow

Annual Rainfall 34.2"

10% below US avg

Snowfall 2.8"

Wettest Month (Jan) 3.78"

Driest Month (Jul) 0.04"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Very High
Risk Score	99.8 / 100
Social Vulnerability	27.5 / 100
Community Resilience	91.2 / 100

Hazard Breakdown

Tornado	Relatively Moderate
Earthquake	Very High
Wildfire	Relatively High
Flood	Very High
Hail	Relatively Low
Strong Wind	Very Low
Heat Wave	Relatively High
Winter Weather	Very Low
Lightning	Relatively Low
Drought	Relatively Moderate
Cold Wave	No Rating
Landslide	Relatively High
Coastal Flood	Relatively High
Tsunami	Relatively Low
Volcano	Very Low
Avalanche	Very Low

Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

6,042 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	60 km	11 km
Apr 18, 1990	5 km NNW of Aromas, California	M5.4	96 km	5 km
Apr 18, 1990	4 km E of Interlaken, California	M5.1	92 km	7 km
Aug 12, 1998	10 km SW of Ridgemark, California	M5.1	120 km	9 km
Jan 16, 1993	9 km E of Gilroy, California	M4.9	93 km	7 km
Apr 23, 1995	22 km NNE of Soledad, California	M4.9	145 km	7 km
May 14, 2002	5 km SSW of Gilroy, California	M4.9	94 km	7 km
Apr 19, 1996	2 km E of Aromas, California	M4.9	102 km	5 km
Sep 3, 2000	5 km WSW of Yountville, California	M4.9	80 km	9 km
Apr 18, 1990	4 km NNW of Aromas, California	M4.9	96 km	6 km
Sep 4, 1995	13 km SW of Middletown, California	M4.8	124 km	7 km
May 12, 2006	7 km W of Cobb, California	M4.7	140 km	4 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	49 km	8 km
Apr 18, 1990	4 km N of Aromas, California	M4.7	97 km	4 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	55 km	9 km
Jan 2, 2025	4 km NW of Cobb, CA	M4.7	140 km	1 km
Aug 27, 2011	21 km NE of Soledad, California	M4.6	147 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	68 km	8 km
Jan 11, 2000	6 km N of Geyserville, California	M4.6	141 km	6 km

Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

68 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
Apr 27, 1953	EF2	83 km	0.1 mi	0
Jan 11, 1951	EF2	47 km	5.7 mi	0
Dec 14, 2024	EF1	80 km	0.3 mi	0
Jan 23, 2010	EF1	22 km	1.6 mi	0
Apr 14, 2006	EF1	83 km	0.5 mi	0
Mar 20, 2005	EF1	45 km	3.0 mi	0
Dec 20, 2001	EF1	89 km	0.5 mi	0
May 5, 1998	EF1	46 km	0.3 mi	0
Dec 12, 1996	EF1	95 km	0.6 mi	0
Apr 19, 1988	EF1	82 km	0.2 mi	0
Jan 14, 1980	EF1	32 km	0.3 mi	0
Mar 4, 1978	EF1	98 km	2.5 mi	0
Mar 1, 1978	EF1	89 km	1.5 mi	0
May 31, 1967	EF1	60 km	0.1 mi	0
Apr 1, 1965	EF1	88 km	0.1 mi	0
Apr 1, 1958	EF1	40 km	0.2 mi	0
Jan 14, 2023	EF0	93 km	0.3 mi	0
Nov 8, 2022	EF0	83 km	0.8 mi	0
Sep 28, 2019	EF0	92 km	1.7 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	17 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	81 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	44 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	51 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	63 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Clear Lake (153 km).

Name	Type	Elevation	Last Eruption	Distance
Clear Lake	Volcanic field	1,439 m (4,721 ft)	Unknown	153 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	49 km
2020	CZU AUG LIGHTNING	85,894	73 km
2017	NUNS	56,883	82 km
2017	ATLAS	51,664	72 km
2007	LICK	47,424	75 km
2006	CANYON	36,851	69 km
1988	MILLER	35,750	75 km
2003	ANNIE	17,383	85 km
2024	CORRAL	16,138	44 km
2018	WAVERLY	12,238	99 km
2009	CORRAL	12,006	44 km
1995	VISION	11,931	87 km
1985	LEXINGTON	11,550	69 km
2015	WRAGG	8,455	81 km
2009	LOCKHEED	8,287	80 km
2003	BIRD	7,727	58 km
2014	MONTICELLO	6,984	87 km
1984	SITE 300 3	6,911	42 km
2005	TESLA	6,638	34 km
2003	DEL PUERTO	6,441	60 km

Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	47°F (8°C)	3.8 in	Coldest, Wettest
February	51°F (10°C)	3.2 in
March	53°F (12°C)	3.0 in
April	57°F (14°C)	1.2 in
May	61°F (16°C)	0.4 in
June	66°F (19°C)	0.1 in
July	68°F (20°C)	0.0 in	Driest
August	70°F (21°C)	0.1 in	Warmest
September	69°F (20°C)	0.3 in
October	63°F (17°C)	1.1 in
November	54°F (12°C)	2.6 in
December	47°F (9°C)	2.9 in

San Ramon has a seasonal temperature swing of 23°F / from 47°F in January to 70°F in August. Total annual precipitation is 18.7 inches, with January being the wettest month (3.8") and July the driest (0.0").

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