Weather & Climate in Mount Hermon, CA

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

Mount Hermon enjoys a temperate climate with an average annual temperature of 61°F (16°C). Winters average 51°F in January while summers reach 70°F in July / relatively mild seasonal variation. The area gets 305 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 49.6 inches (wetter than the 38-inch national average). Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 476 feet.

Temperature

51°F Jan (11°C) 70°F Jul (21°C)

Annual Average	60.5°F
	12% above US avg
January Average	51°F (11°C)
July Average	70°F (21°C)
Sunny Days	305 days/yr

Geography

Elevation	476 ft (145 m)
Area	0.3 sq mi (0.9 km²)
Population Density	1,851/sq mi
Coordinates	37.0510°N, 122.0533°W
Timezone	America/Los_Angeles
County	Santa Cruz County County
Nearest Airport	Norman Y Mineta San Jose International (SJC) 23 miles away

Precipitation & Snow

Annual Rainfall 49.6"

31% above US avg

Snowfall 0.1"

Wettest Month (Jan) 6.89"

Driest Month (Jul) 0.12"

Air Quality

AQI Median	48.0
Rating	Good

Natural Hazard Risk

Overall Risk	Relatively High
Risk Score	97.8 / 100
Social Vulnerability	28.1 / 100
Community Resilience	71.1 / 100

Hazard Breakdown

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

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

Earthquake History

4,166 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	131 km	11 km
Apr 18, 1990	5 km NNW of Aromas, California	M5.4	38 km	5 km
Oct 21, 2012	24 km NE of San Lucas, California	M5.3	135 km	9 km
Aug 12, 1998	10 km SW of Ridgemark, California	M5.1	62 km	9 km
Apr 18, 1990	4 km E of Interlaken, California	M5.1	34 km	7 km
Jan 16, 1993	9 km E of Gilroy, California	M4.9	53 km	7 km
Apr 19, 1996	2 km E of Aromas, California	M4.9	43 km	5 km
Apr 18, 1990	4 km NNW of Aromas, California	M4.9	38 km	6 km
Apr 23, 1995	22 km NNE of Soledad, California	M4.9	91 km	7 km
May 14, 2002	5 km SSW of Gilroy, California	M4.9	42 km	7 km
Apr 18, 1990	4 km N of Aromas, California	M4.7	39 km	4 km
May 21, 1996	8 km ESE of East Foothills, California	M4.7	45 km	8 km
Feb 4, 1991	33 km SE of Big Sur, California	M4.7	121 km	9 km
Aug 11, 1993	14 km ESE of Alum Rock, California	M4.7	44 km	9 km
Aug 27, 2011	21 km NE of Soledad, California	M4.6	93 km	8 km
Aug 18, 1999	0 km S of Bolinas, California	M4.6	110 km	8 km
Mar 24, 1991	1 km NNE of Interlaken, California	M4.6	31 km	15 km
Sep 19, 2023	15 km SW of Westley, CA	M4.5	80 km	4 km
Jan 12, 2011	9 km SSE of San Juan Bautista, California	M4.5	59 km	8 km
Jan 20, 2015	27 km ENE of Greenfield, California	M4.4	118 km	9 km

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

Tornado History

33 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 10 injuries.

Date	Rating	Distance	Path	Fatalities
May 5, 1998	EF2	36 km	0.6 mi	0
Mar 11, 1985	EF2	62 km	0.5 mi	0
Jan 11, 1951	EF2	36 km	5.7 mi	0
Dec 14, 2024	EF1	2 km	0.3 mi	0
Jan 23, 2010	EF1	99 km	1.6 mi	0
Mar 20, 2005	EF1	74 km	3.0 mi	0
Dec 20, 2001	EF1	26 km	0.5 mi	0
May 5, 1998	EF1	37 km	0.3 mi	0
Dec 6, 1992	EF1	53 km	1.0 mi	0
Dec 6, 1992	EF1	57 km	7.0 mi	0
Jan 14, 1980	EF1	50 km	0.3 mi	0
Apr 1, 1965	EF1	24 km	0.1 mi	0
Apr 1, 1958	EF1	69 km	0.2 mi	0
Jan 6, 2019	EF0	10 km	0.1 mi	0
Jan 6, 2019	EF0	11 km	0.5 mi	0
Jan 6, 2016	EF0	61 km	0.6 mi	0
Dec 22, 2012	EF0	28 km	1.1 mi	0
Apr 14, 2007	EF0	41 km	0.2 mi	0
Dec 26, 2005	EF0	95 km	0.3 mi	0
Dec 5, 1998	EF0	8 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	72 km
1989	N. CALIFORNIA	Earthquake	1.0 m	62	15 km
1856	N. CALIFORNIA	Eruption + Earthquake	0.6 m	—	55 km
1906	N. CALIFORNIA	Eruption + Earthquake	0.1 m	—	82 km
1865	N. CALIFORNIA	Eruption + Earthquake	—	—	21 km

Source: NOAA/NCEI Historical Tsunami Database.

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	69 km
2016	SOBERANES	131,921	87 km
2020	CZU AUG LIGHTNING	85,894	18 km
2020	RIVER	51,582	76 km
2007	LICK	47,424	59 km
2006	CANYON	36,851	72 km
1999	KIRK COMPLEX (FIVE)	36,162	94 km
2003	ANNIE	17,383	74 km
2024	CORRAL	16,138	84 km
2009	CORRAL	12,006	78 km
1985	LEXINGTON	11,550	16 km
2009	LOCKHEED	8,287	15 km
2003	BIRD	7,727	84 km
2020	CARMEL	7,299	79 km
1984	SITE 300 3	6,911	84 km
2009	GLORIA	6,686	94 km
2005	TESLA	6,638	80 km
2003	DEL PUERTO	6,441	72 km
2006	MIDWAY	6,243	84 km
2020	CREWS	5,802	53 km

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

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	51°F (11°C)	6.9 in	Wettest
February	51°F (10°C)	5.7 in
March	52°F (11°C)	5.2 in
April	55°F (13°C)	2.2 in
May	58°F (15°C)	0.5 in
June	62°F (17°C)	0.2 in
July	70°F (21°C)	0.1 in	Warmest, Driest
August	66°F (19°C)	0.1 in
September	64°F (18°C)	0.4 in
October	61°F (16°C)	1.6 in
November	53°F (12°C)	4.7 in
December	49°F (9°C)	5.1 in	Coldest

Mount Hermon has a seasonal temperature swing of 21°F / from 49°F in December to 70°F in July. Total annual precipitation is 32.7 inches, with January being the wettest month (6.9") and July the driest (0.1").

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