Weather & Climate in Hilmar-Irwin, CA

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

Hilmar-Irwin enjoys a temperate climate with an average annual temperature of 60°F (15°C). Winters average 46°F in January while summers reach 75°F in July. Annual precipitation totals 10.4 inches (drier than the 38-inch national average). Air quality is rated Moderate with a median AQI of 52. 46% of days have good air quality. The city sits at an elevation of 95 feet.

Temperature

46°F Jan (8°C) 75°F Jul (24°C)
Annual Average59.6°F
10% above US avg
January Average46°F (8°C)
July Average75°F (24°C)

Geography

Elevation95 ft (29 m)
Area1.5 sq mi (3.9 km²)
Population Density1,607/sq mi
Coordinates37.4045°N, 120.8504°W
TimezoneAmerica/Los_Angeles
CountyMerced County County
Nearest AirportMerced Yosemite Regional (MCE)
21 miles away

Precipitation & Snow

Annual Rainfall 10.4"
73% below US avg
Snowfall 0.0"
Wettest Month (Jan) 2.40"
Driest Month (Jul) 0.01"

Air Quality

AQI Median52.0
RatingModerate
Good Days %45.9%
Unhealthy Days35

Natural Hazard Risk

Overall RiskRelatively High
Risk Score96.9 / 100
Social Vulnerability61.7 / 100
Community Resilience7.3 / 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 High
Winter Weather Very Low
Lightning Relatively High
Drought Very High
Cold Wave No Rating
Landslide Very Low
Volcano Very Low
Avalanche Very Low
Source: FEMA National Risk Index v1.20 (Dec 2025)

Earthquake History

4,423 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.4.

Apr 18, 1990 5 km NNW of Aromas, California M5.4 89 km 5 km
Oct 21, 2012 24 km NE of San Lucas, California M5.3 122 km 9 km
Aug 12, 1998 10 km SW of Ridgemark, California M5.1 90 km 9 km
Apr 18, 1990 4 km E of Interlaken, California M5.1 89 km 7 km
Jan 16, 1993 9 km E of Gilroy, California M4.9 69 km 7 km
Apr 23, 1995 22 km NNE of Soledad, California M4.9 95 km 7 km
Apr 18, 1990 4 km NNW of Aromas, California M4.9 89 km 6 km
May 14, 2002 5 km SSW of Gilroy, California M4.9 82 km 7 km
Apr 19, 1996 2 km E of Aromas, California M4.9 89 km 5 km
Apr 18, 1990 4 km N of Aromas, California M4.7 88 km 4 km
May 21, 1996 8 km ESE of East Foothills, California M4.7 77 km 8 km
Aug 11, 1993 14 km ESE of Alum Rock, California M4.7 74 km 9 km
Aug 27, 2011 21 km NE of Soledad, California M4.6 96 km 8 km
Mar 24, 1991 1 km NNE of Interlaken, California M4.6 92 km 15 km
Sep 19, 2023 15 km SW of Westley, CA M4.5 40 km 4 km
Jan 12, 2011 9 km SSE of San Juan Bautista, California M4.5 91 km 8 km
Jan 20, 2015 27 km ENE of Greenfield, California M4.4 109 km 9 km
Apr 4, 2023 1km NNW of Tres Pinos, CA M4.4 79 km 10 km
Apr 18, 1990 5 km E of Interlaken, California M4.4 89 km 7 km
Apr 28, 1990 3 km SSE of North Gate, California M4.4 112 km 7 km
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.

Tornado History

76 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 2 injuries.

Date Rating Distance Path Fatalities
Mar 11, 1985 EF2 79 km 0.5 mi 0
Apr 27, 1953 EF2 30 km 0.1 mi 0
Mar 11, 2023 EF1 65 km 0.8 mi 0
Jan 10, 2023 EF1 76 km 0.4 mi 0
Nov 15, 2015 EF1 14 km 3.0 mi 0
Jan 23, 2010 EF1 99 km 1.6 mi 0
Apr 14, 2006 EF1 30 km 0.5 mi 0
Dec 16, 2002 EF1 30 km 1.3 mi 0
May 20, 2002 EF1 84 km 2.7 mi 0
Dec 20, 2001 EF1 96 km 0.5 mi 0
Feb 14, 1998 EF1 68 km 3.0 mi 0
Dec 12, 1996 EF1 41 km 0.6 mi 0
Nov 22, 1996 EF1 36 km 0.2 mi 0
Jan 14, 1995 EF1 60 km 1.0 mi 0
Apr 19, 1988 EF1 89 km 0.2 mi 0
Jan 14, 1980 EF1 91 km 0.3 mi 0
Mar 4, 1978 EF1 2 km 1.0 mi 0
Mar 4, 1978 EF1 25 km 2.5 mi 0
Mar 1, 1978 EF1 30 km 1.5 mi 0
May 31, 1967 EF1 74 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 30 115 km
1989 N. CALIFORNIA Earthquake 1.0 m 62 100 km
1856 N. CALIFORNIA Eruption + Earthquake 0.6 m - 128 km
1906 N. CALIFORNIA Eruption + Earthquake 0.1 m - 149 km
1865 N. CALIFORNIA Eruption + Earthquake - - 96 km
Source: NOAA/NCEI Historical Tsunami Database.

Nearby Volcanoes

3 volcanoes within 200 km. Closest: Mammoth Mountain (162 km).

Name Type Elevation Last Eruption Distance
Mammoth Mountain Lava dome(s) 3,369 m (11,053 ft) 1260 162 km
Mono-Inyo Craters Lava dome(s) 2,796 m (9,173 ft) 1380 167 km
Mono Lake Volcanic Field Pyroclastic cone(s) 2,121 m (6,959 ft) 1790 173 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 58 km
2013 RIM 257,084 96 km
2018 FERGUSON 97,307 96 km
2017 DETWILER 83,297 66 km
2015 BUTTE 72,894 98 km
1987 PAPER 49,296 85 km
1987 LARSON 49,250 88 km
2007 LICK 47,424 55 km
1987 HAMM 39,333 82 km
2006 CANYON 36,851 44 km
2008 TELEGRAPH 33,479 77 km
2022 OAK 19,408 88 km
1992 GULCH 18,019 92 km
1990 A-ROCK 17,706 99 km
1996 ROGGE 17,559 85 km
2003 ANNIE 17,383 40 km
1996 MERCY 16,993 60 km
2024 CORRAL 16,138 60 km
1996 PANOCHE II 14,760 94 km
2001 DARBY 14,734 100 km
Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month Avg Temperature Precipitation Summary
January 46°F (8°C) 2.4 in Wettest
February 49°F (10°C) 2.0 in
March 54°F (12°C) 1.8 in
April 57°F (14°C) 0.7 in
May 64°F (18°C) 0.4 in
June 70°F (21°C) 0.1 in
July 75°F (24°C) 0.0 in Warmest, Driest
August 73°F (23°C) 0.0 in
September 70°F (21°C) 0.1 in
October 62°F (17°C) 0.6 in
November 52°F (11°C) 0.9 in
December 45°F (7°C) 1.5 in Coldest

Hilmar-Irwin has a seasonal temperature swing of 30°F / from 45°F in December to 75°F in July. Total annual precipitation is 10.5 inches, with January being the wettest month (2.4") and July the driest (0.0").

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