Weather & Climate in Three Rocks, CA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Three Rocks enjoys a temperate climate with an average annual temperature of 64°F (18°C). Winters average 48°F in January while summers reach 81°F in July. Annual precipitation totals 7.2 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 43. 71% of days have good air quality. The city sits at an elevation of 409 feet.
Temperature
48°F Jan (9°C)
81°F Jul (27°C)
| Annual Average | 64.3°F |
| 19% above US avg | |
| January Average | 48°F (9°C) |
| July Average | 81°F (27°C) |
Geography
| Elevation | 409 ft (125 m) |
| Area | 0.8 sq mi (1.9 km²) |
| Population Density | 240/sq mi |
| Coordinates | 36.5051°N, 120.3935°W |
| Timezone | America/Los_Angeles |
| County | San Benito County County |
| Nearest Airport | Fresno Yosemite International (FAT) 42 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
| Good Days % | 71.0% |
| Unhealthy Days | 1 |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 85.2 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 56.0 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Relatively Moderate |
| Flood | Relatively Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Relatively Low |
| Winter Weather | Very Low |
| Lightning | Very Low |
| Drought | Relatively High |
| Cold Wave | No Rating |
| Landslide | Relatively Moderate |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
4,925 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M6.0.
| Sep 28, 2004 | 2004 Parkfield, California Earthquake | M6.0 | 76 km | 8 km |
| Apr 18, 1990 | 5 km NNW of Aromas, California | M5.4 | 122 km | 5 km |
| Oct 21, 2012 | 24 km NE of San Lucas, California | M5.3 | 47 km | 9 km |
| Sep 17, 1991 | 22 km NW of San Simeon, California | M5.2 | 115 km | 9 km |
| Apr 18, 1990 | 4 km E of Interlaken, California | M5.1 | 126 km | 7 km |
| Aug 12, 1998 | 10 km SW of Ridgemark, California | M5.1 | 99 km | 9 km |
| Sep 29, 2004 | 8 km NW of Parkfield, California | M5.0 | 62 km | 11 km |
| Jan 16, 1993 | 9 km E of Gilroy, California | M4.9 | 111 km | 7 km |
| May 14, 2002 | 5 km SSW of Gilroy, California | M4.9 | 119 km | 7 km |
| Apr 18, 1990 | 4 km NNW of Aromas, California | M4.9 | 122 km | 6 km |
| Dec 20, 1994 | 3 km NW of Parkfield, California | M4.9 | 66 km | 8 km |
| Apr 23, 1995 | 22 km NNE of Soledad, California | M4.9 | 73 km | 7 km |
| Apr 19, 1996 | 2 km E of Aromas, California | M4.9 | 117 km | 5 km |
| Sep 30, 2004 | 13 km NW of Parkfield, California | M4.9 | 59 km | 10 km |
| Feb 24, 2016 | 6km SSW of Wasco, CA | M4.9 | 141 km | 22 km |
| Nov 14, 1993 | 8 km NW of Parkfield, California | M4.8 | 62 km | 11 km |
| Sep 28, 2004 | 12 km SE of Parkfield, California | M4.7 | 78 km | 6 km |
| Apr 18, 1990 | 4 km N of Aromas, California | M4.7 | 121 km | 4 km |
| Feb 4, 1991 | 33 km SE of Big Sur, California | M4.7 | 118 km | 9 km |
| Aug 11, 1993 | 14 km ESE of Alum Rock, California | M4.7 | 145 km | 9 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
72 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 5 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 11, 1985 | EF2 | 98 km | 0.5 mi | 0 |
| Apr 5, 1980 | EF2 | 64 km | 15.0 mi | 0 |
| Mar 22, 1962 | EF2 | 62 km | 0.5 mi | 0 |
| Jan 17, 2019 | EF1 | 83 km | 0.3 mi | 0 |
| Dec 16, 2002 | EF1 | 92 km | 1.3 mi | 0 |
| May 20, 2002 | EF1 | 53 km | 2.7 mi | 0 |
| Feb 14, 1998 | EF1 | 41 km | 3.0 mi | 0 |
| Nov 22, 1996 | EF1 | 46 km | 0.8 mi | 0 |
| Nov 22, 1996 | EF1 | 92 km | 0.2 mi | 0 |
| Jan 14, 1995 | EF1 | 69 km | 1.0 mi | 0 |
| Feb 28, 1991 | EF1 | 86 km | 0.2 mi | 0 |
| Mar 8, 1986 | EF1 | 67 km | 4.0 mi | 0 |
| Mar 28, 1982 | EF1 | 70 km | 5.0 mi | 0 |
| Feb 19, 1980 | EF1 | 67 km | 1.7 mi | 0 |
| Mar 14, 1979 | EF1 | 66 km | 2.0 mi | 0 |
| Apr 22, 1967 | EF1 | 33 km | 0.1 mi | 0 |
| Apr 22, 1967 | EF1 | 73 km | 1.0 mi | 0 |
| Apr 21, 1967 | EF1 | 59 km | 0.1 mi | 0 |
| May 19, 1957 | EF1 | 55 km | 0.1 mi | 0 |
| Mar 1, 2024 | EF0 | 65 km | 0.4 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Tsunami History
2 tsunamis recorded within 500 km. Highest wave on record: 1.0 m (3 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 145 km |
| 1901 | MONTEREY BAY, N. CALIFORNIA | Eruption + Earthquake | - | - | 57 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
3 volcanoes within 200 km. Closest: Mammoth Mountain (174 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Mammoth Mountain | Lava dome(s) | 3,369 m (11,053 ft) | 1260 | 174 km |
| Golden Trout Creek | Volcanic field | 2,886 m (9,469 ft) | -5550 | 186 km |
| Mono-Inyo Craters | Lava dome(s) | 2,796 m (9,173 ft) | 1380 | 188 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: BASIN COMPLEX (INDIANS) (59,095 acres, 2008).
| Year | Name | Acres Burned | Distance |
| 2008 | BASIN COMPLEX (INDIANS) | 59,095 | 97 km |
| 2017 | GARZA | 48,404 | 62 km |
| 1985 | CHERRY | 41,654 | 85 km |
| 2005 | UNNAMED | 39,070 | 98 km |
| 2020 | MINERAL | 29,901 | 40 km |
| 1984 | UNNAMED | 23,122 | 99 km |
| 1993 | ORCHARD | 22,309 | 90 km |
| 1996 | SKYLINE | 21,694 | 65 km |
| 1985 | LOSGATOSIV | 20,357 | 22 km |
| 1996 | UNNAMED | 19,243 | 98 km |
| 2024 | BOONE | 17,701 | 41 km |
| 1996 | MERCY | 16,993 | 55 km |
| 1996 | PANOCHE II | 14,760 | 22 km |
| 1984 | BONANZA | 12,105 | 56 km |
| 2006 | RICO | 11,807 | 57 km |
| 2017 | ELM 2 | 10,765 | 48 km |
| 1984 | UNNAMED | 10,420 | 95 km |
| 1992 | UNNAMED | 10,235 | 98 km |
| 1996 | HWY 41 | 9,537 | 85 km |
| 1997 | UNNAMED | 9,396 | 85 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 48°F (9°C) | 1.5 in | Wettest |
| February | 53°F (11°C) | 1.3 in | |
| March | 57°F (14°C) | 1.4 in | |
| April | 62°F (17°C) | 0.5 in | |
| May | 70°F (21°C) | 0.4 in | |
| June | 76°F (24°C) | 0.0 in | |
| July | 81°F (27°C) | 0.0 in | Warmest |
| August | 80°F (27°C) | 0.0 in | Driest |
| September | 76°F (24°C) | 0.0 in | |
| October | 66°F (19°C) | 0.4 in | |
| November | 55°F (13°C) | 0.5 in | |
| December | 48°F (9°C) | 1.1 in | Coldest |
Three Rocks has a seasonal temperature swing of 33°F / from 48°F in December to 81°F in July. Total annual precipitation is 7.2 inches, with January being the wettest month (1.5") and August the driest (0.0").