Weather & Climate in McSwain, CA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
McSwain enjoys a temperate climate with an average annual temperature of 62°F (17°C). Winters average 46°F in January while summers reach 79°F in July. Annual precipitation totals 11.8 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 143 feet.
Temperature
46°F Jan (8°C)
79°F Jul (26°C)
| Annual Average | 62.3°F |
| 15% above US avg | |
| January Average | 46°F (8°C) |
| July Average | 79°F (26°C) |
Geography
| Elevation | 143 ft (44 m) |
| Area | 6.0 sq mi (15.6 km²) |
| Population Density | 921/sq mi |
| Coordinates | 37.3145°N, 120.5868°W |
| Timezone | America/Los_Angeles |
| County | Merced County County |
| Nearest Airport | Merced Yosemite Regional (MCE) 5 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 52.0 |
| Rating | Moderate |
| Good Days % | 45.9% |
| Unhealthy Days | 35 |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 96.9 / 100 |
| Social Vulnerability | 61.7 / 100 |
| Community Resilience | 7.3 / 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
4,830 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 | 104 km | 5 km |
| Oct 21, 2012 | 24 km NE of San Lucas, California | M5.3 | 114 km | 9 km |
| Apr 18, 1990 | 4 km E of Interlaken, California | M5.1 | 105 km | 7 km |
| Aug 12, 1998 | 10 km SW of Ridgemark, California | M5.1 | 100 km | 9 km |
| Jan 16, 1993 | 9 km E of Gilroy, California | M4.9 | 84 km | 7 km |
| Apr 23, 1995 | 22 km NNE of Soledad, California | M4.9 | 96 km | 7 km |
| May 14, 2002 | 5 km SSW of Gilroy, California | M4.9 | 98 km | 7 km |
| Apr 19, 1996 | 2 km E of Aromas, California | M4.9 | 103 km | 5 km |
| Apr 18, 1990 | 4 km NNW of Aromas, California | M4.9 | 104 km | 6 km |
| Nov 30, 1997 | 2 km ESE of Mammoth Lakes, California | M4.9 | 149 km | 5 km |
| Sep 30, 2004 | 13 km NW of Parkfield, California | M4.9 | 148 km | 10 km |
| Nov 22, 1997 | 3 km ESE of Mammoth Lakes, California | M4.9 | 150 km | 5 km |
| Apr 18, 1990 | 4 km N of Aromas, California | M4.7 | 103 km | 4 km |
| May 21, 1996 | 8 km ESE of East Foothills, California | M4.7 | 101 km | 8 km |
| Aug 11, 1993 | 14 km ESE of Alum Rock, California | M4.7 | 97 km | 9 km |
| Aug 27, 2011 | 21 km NE of Soledad, California | M4.6 | 97 km | 8 km |
| Mar 24, 1991 | 1 km NNE of Interlaken, California | M4.6 | 108 km | 15 km |
| Sep 19, 2023 | 15 km SW of Westley, CA | M4.5 | 64 km | 4 km |
| Nov 22, 1997 | California-Nevada border region | M4.5 | 149 km | 6 km |
| Jan 12, 2011 | 9 km SSE of San Juan Bautista, California | M4.5 | 101 km | 8 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
79 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 3 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 11, 1985 | EF2 | 89 km | 0.5 mi | 0 |
| Mar 22, 1962 | EF2 | 90 km | 0.5 mi | 0 |
| Apr 27, 1953 | EF2 | 52 km | 0.1 mi | 0 |
| Mar 11, 2023 | EF1 | 69 km | 0.8 mi | 0 |
| Jan 10, 2023 | EF1 | 87 km | 0.4 mi | 0 |
| Nov 15, 2015 | EF1 | 31 km | 3.0 mi | 0 |
| Apr 14, 2006 | EF1 | 52 km | 0.5 mi | 0 |
| Dec 16, 2002 | EF1 | 6 km | 1.3 mi | 0 |
| May 20, 2002 | EF1 | 60 km | 2.7 mi | 0 |
| Feb 14, 1998 | EF1 | 50 km | 3.0 mi | 0 |
| Dec 12, 1996 | EF1 | 56 km | 0.6 mi | 0 |
| Nov 22, 1996 | EF1 | 12 km | 0.2 mi | 0 |
| Jan 14, 1995 | EF1 | 35 km | 1.0 mi | 0 |
| Feb 19, 1980 | EF1 | 98 km | 1.7 mi | 0 |
| Mar 4, 1978 | EF1 | 41 km | 2.5 mi | 0 |
| Mar 4, 1978 | EF1 | 26 km | 1.0 mi | 0 |
| Mar 1, 1978 | EF1 | 50 km | 1.5 mi | 0 |
| May 31, 1967 | EF1 | 96 km | 0.1 mi | 0 |
| Apr 22, 1967 | EF1 | 28 km | 1.0 mi | 0 |
| Apr 22, 1967 | EF1 | 69 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Tsunami History
4 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 | 140 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 119 km |
| 1901 | MONTEREY BAY, N. CALIFORNIA | Eruption + Earthquake | - | - | 146 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 117 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
3 volcanoes within 200 km. Closest: Mammoth Mountain (142 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Mammoth Mountain | Lava dome(s) | 3,369 m (11,053 ft) | 1260 | 142 km |
| Mono-Inyo Craters | Lava dome(s) | 2,796 m (9,173 ft) | 1380 | 148 km |
| Mono Lake Volcanic Field | Pyroclastic cone(s) | 2,121 m (6,959 ft) | 1790 | 157 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 | 83 km |
| 2013 | RIM | 257,084 | 86 km |
| 2018 | FERGUSON | 97,307 | 78 km |
| 2017 | DETWILER | 83,297 | 49 km |
| 1996 | ACKERSON COMPLEX (ACKERSON) | 58,161 | 95 km |
| 1987 | PAPER | 49,296 | 78 km |
| 1987 | LARSON | 49,250 | 74 km |
| 2007 | LICK | 47,424 | 75 km |
| 1987 | HAMM | 39,333 | 71 km |
| 2006 | CANYON | 36,851 | 67 km |
| 2008 | TELEGRAPH | 33,479 | 60 km |
| 2022 | OAK | 19,408 | 69 km |
| 1992 | GULCH | 18,019 | 97 km |
| 1990 | A-ROCK | 17,706 | 82 km |
| 1996 | ROGGE | 17,559 | 77 km |
| 2003 | ANNIE | 17,383 | 59 km |
| 1996 | MERCY | 16,993 | 54 km |
| 2024 | CORRAL | 16,138 | 85 km |
| 1996 | PANOCHE II | 14,760 | 82 km |
| 2017 | RAILROAD | 12,765 | 87 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 | 51°F (10°C) | 2.2 in | |
| March | 55°F (13°C) | 1.8 in | |
| April | 60°F (15°C) | 1.1 in | |
| May | 67°F (20°C) | 0.6 in | |
| June | 74°F (23°C) | 0.1 in | |
| July | 79°F (26°C) | 0.0 in | Warmest, Driest |
| August | 78°F (26°C) | 0.0 in | |
| September | 74°F (23°C) | 0.1 in | |
| October | 64°F (18°C) | 0.6 in | |
| November | 54°F (12°C) | 1.0 in | |
| December | 46°F (8°C) | 1.9 in | Coldest |
McSwain has a seasonal temperature swing of 33°F / from 46°F in December to 79°F in July. Total annual precipitation is 11.8 inches, with January being the wettest month (2.4") and July the driest (0.0").