Weather & Climate in Diablo Grande, CA

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

Diablo Grande enjoys a temperate climate with an average annual temperature of 65°F (18°C). Winters average 49°F in January while summers reach 81°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 11.7 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 1,060 feet.

Temperature

49°F Jan (10°C) 81°F Jul (27°C)

Annual Average	65.0°F
	20% above US avg
January Average	49°F (10°C)
July Average	81°F (27°C)
Sunny Days	330 days/yr

Geography

Elevation	1,060 ft (323 m)
Area	5.1 sq mi (13.2 km²)
Population Density	346/sq mi
Coordinates	37.3990°N, 121.2635°W
Timezone	America/Los_Angeles
County	Stanislaus County County
Nearest Airport	Norman Y Mineta San Jose International (SJC) 37 miles away

Precipitation & Snow

Annual Rainfall 11.7"

69% below US avg

Snowfall 0.0"

Wettest Month (Jan) 3.46"

Driest Month (Jul) 0.04"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively High
Risk Score	96.9 / 100
Social Vulnerability	32.0 / 100
Community Resilience	33.9 / 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 Moderate
Winter Weather	Relatively Low
Lightning	Relatively High
Drought	Very High
Cold Wave	No Rating
Landslide	Relatively Low
Volcano	Very Low
Avalanche	Very Low

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

Earthquake History

4,341 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	129 km	11 km
Apr 18, 1990	5 km NNW of Aromas, California	M5.4	63 km	5 km
Oct 21, 2012	24 km NE of San Lucas, California	M5.3	126 km	9 km
Aug 12, 1998	10 km SW of Ridgemark, California	M5.1	74 km	9 km
Apr 18, 1990	4 km E of Interlaken, California	M5.1	62 km	7 km
Jan 16, 1993	9 km E of Gilroy, California	M4.9	46 km	7 km
May 14, 2002	5 km SSW of Gilroy, California	M4.9	57 km	7 km
Apr 18, 1990	4 km NNW of Aromas, California	M4.9	63 km	6 km
Apr 23, 1995	22 km NNE of Soledad, California	M4.9	89 km	7 km
Apr 19, 1996	2 km E of Aromas, California	M4.9	65 km	5 km
Sep 3, 2000	5 km WSW of Yountville, California	M4.9	149 km	9 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	41 km	8 km
Apr 18, 1990	4 km N of Aromas, California	M4.7	62 km	4 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	38 km	9 km
Aug 27, 2011	21 km NE of Soledad, California	M4.6	91 km	8 km
Mar 24, 1991	1 km NNE of Interlaken, California	M4.6	63 km	15 km
Aug 18, 1999	0 km S of Bolinas, California	M4.6	137 km	8 km
Sep 19, 2023	15 km SW of Westley, CA	M4.5	5 km	4 km
Jan 12, 2011	9 km SSE of San Juan Bautista, California	M4.5	73 km	8 km
Jan 20, 2015	27 km ENE of Greenfield, California	M4.4	111 km	9 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: 9 injuries.

Date	Rating	Distance	Path	Fatalities
May 5, 1998	EF2	68 km	0.6 mi	0
Mar 11, 1985	EF2	62 km	0.5 mi	0
Apr 27, 1953	EF2	36 km	0.1 mi	0
Jan 11, 1951	EF2	76 km	5.7 mi	0
Dec 14, 2024	EF1	79 km	0.3 mi	0
Mar 11, 2023	EF1	88 km	0.8 mi	0
Jan 10, 2023	EF1	88 km	0.4 mi	0
Nov 15, 2015	EF1	42 km	3.0 mi	0
Jan 23, 2010	EF1	72 km	1.6 mi	0
Apr 14, 2006	EF1	36 km	0.5 mi	0
Dec 16, 2002	EF1	66 km	1.3 mi	0
Dec 20, 2001	EF1	66 km	0.5 mi	0
May 5, 1998	EF1	76 km	0.3 mi	0
Feb 14, 1998	EF1	91 km	3.0 mi	0
Dec 12, 1996	EF1	55 km	0.6 mi	0
Nov 22, 1996	EF1	72 km	0.2 mi	0
Jan 14, 1995	EF1	93 km	1.0 mi	0
Apr 19, 1988	EF1	86 km	0.2 mi	0
Jan 14, 1980	EF1	55 km	0.3 mi	0
Mar 4, 1978	EF1	37 km	1.0 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	81 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	68 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	92 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	114 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	61 km

Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

1 volcano within 200 km. Closest: Mammoth Mountain (199 km).

Name	Type	Elevation	Last Eruption	Distance
Mammoth Mountain	Lava dome(s)	3,369 m (11,053 ft)	1260	199 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	23 km
2020	CZU AUG LIGHTNING	85,894	89 km
2007	LICK	47,424	24 km
2006	CANYON	36,851	8 km
2003	ANNIE	17,383	19 km
1996	MERCY	16,993	71 km
2024	CORRAL	16,138	32 km
2018	WAVERLY	12,238	76 km
1984	BONANZA	12,105	78 km
2009	CORRAL	12,006	29 km
1985	LEXINGTON	11,550	64 km
2001	CREEK	9,793	100 km
1992	MOCCASIN	9,565	98 km
2009	LOCKHEED	8,287	91 km
2000	HUNTER	7,734	99 km
2003	BIRD	7,727	18 km
1985	PONOCHE 2	7,508	87 km
1984	SITE 300 3	6,911	34 km
2005	TESLA	6,638	39 km
2003	DEL PUERTO	6,441	13 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	49°F (10°C)	3.5 in	Wettest
February	50°F (10°C)	2.8 in
March	53°F (11°C)	2.6 in
April	57°F (14°C)	1.3 in
May	64°F (18°C)	0.3 in
June	71°F (22°C)	0.1 in
July	81°F (27°C)	0.0 in	Warmest, Driest
August	77°F (25°C)	0.1 in
September	73°F (23°C)	0.4 in
October	66°F (19°C)	0.9 in
November	54°F (12°C)	2.7 in
December	47°F (8°C)	2.7 in	Coldest

Diablo Grande has a seasonal temperature swing of 34°F / from 47°F in December to 81°F in July. Total annual precipitation is 17.5 inches, with January being the wettest month (3.5") and July the driest (0.0").

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