Weather & Climate in Grayson, CA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Grayson enjoys a temperate climate with an average annual temperature of 63°F (17°C). Winters average 48°F in January while summers reach 79°F in July. Annual precipitation totals 12.3 inches (drier than the 38-inch national average). Air quality is rated Moderate with a median AQI of 53. 45% of days have good air quality. The city sits at an elevation of 54 feet.
Temperature
48°F Jan (9°C)
79°F Jul (26°C)
| Annual Average | 63.1°F |
| 17% above US avg | |
| January Average | 48°F (9°C) |
| July Average | 79°F (26°C) |
Geography
| Elevation | 54 ft (16 m) |
| Area | 0.2 sq mi (0.5 km²) |
| Population Density | 6,467/sq mi |
| Coordinates | 37.5646°N, 121.1801°W |
| Timezone | America/Los_Angeles |
| County | Stanislaus County County |
| Nearest Airport | Merced Yosemite Regional (MCE) 42 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 53.0 |
| Rating | Moderate |
| Good Days % | 45.4% |
| Unhealthy Days | 38 |
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
4,228 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 | 123 km | 11 km |
| Apr 18, 1990 | 5 km NNW of Aromas, California | M5.4 | 82 km | 5 km |
| Oct 21, 2012 | 24 km NE of San Lucas, California | M5.3 | 143 km | 9 km |
| Apr 18, 1990 | 4 km E of Interlaken, California | M5.1 | 81 km | 7 km |
| Aug 12, 1998 | 10 km SW of Ridgemark, California | M5.1 | 94 km | 9 km |
| Jan 16, 1993 | 9 km E of Gilroy, California | M4.9 | 66 km | 7 km |
| Apr 23, 1995 | 22 km NNE of Soledad, California | M4.9 | 107 km | 7 km |
| Sep 3, 2000 | 5 km WSW of Yountville, California | M4.9 | 141 km | 9 km |
| Apr 18, 1990 | 4 km NNW of Aromas, California | M4.9 | 82 km | 6 km |
| May 14, 2002 | 5 km SSW of Gilroy, California | M4.9 | 76 km | 7 km |
| Apr 19, 1996 | 2 km E of Aromas, California | M4.9 | 85 km | 5 km |
| Apr 18, 1990 | 4 km N of Aromas, California | M4.7 | 82 km | 4 km |
| May 21, 1996 | 8 km ESE of East Foothills, California | M4.7 | 53 km | 8 km |
| Aug 11, 1993 | 14 km ESE of Alum Rock, California | M4.7 | 52 km | 9 km |
| Aug 27, 2011 | 21 km NE of Soledad, California | M4.6 | 109 km | 8 km |
| Mar 24, 1991 | 1 km NNE of Interlaken, California | M4.6 | 82 km | 15 km |
| Aug 18, 1999 | 0 km S of Bolinas, California | M4.6 | 138 km | 8 km |
| Sep 19, 2023 | 15 km SW of Westley, CA | M4.5 | 17 km | 4 km |
| Jan 12, 2011 | 9 km SSE of San Juan Bautista, California | M4.5 | 93 km | 8 km |
| Jan 20, 2015 | 27 km ENE of Greenfield, California | M4.4 | 127 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 | 78 km | 0.6 mi | 0 |
| Mar 11, 1985 | EF2 | 82 km | 0.5 mi | 0 |
| Apr 27, 1953 | EF2 | 19 km | 0.1 mi | 0 |
| Jan 11, 1951 | EF2 | 86 km | 5.7 mi | 0 |
| Dec 14, 2024 | EF1 | 95 km | 0.3 mi | 0 |
| Mar 11, 2023 | EF1 | 70 km | 0.8 mi | 0 |
| Jan 10, 2023 | EF1 | 69 km | 0.4 mi | 0 |
| Nov 15, 2015 | EF1 | 33 km | 3.0 mi | 0 |
| Jan 23, 2010 | EF1 | 65 km | 1.6 mi | 0 |
| Apr 14, 2006 | EF1 | 19 km | 0.5 mi | 0 |
| Dec 16, 2002 | EF1 | 64 km | 1.3 mi | 0 |
| Dec 20, 2001 | EF1 | 85 km | 0.5 mi | 0 |
| May 5, 1998 | EF1 | 86 km | 0.3 mi | 0 |
| Feb 14, 1998 | EF1 | 99 km | 3.0 mi | 0 |
| Dec 12, 1996 | EF1 | 37 km | 0.6 mi | 0 |
| Nov 22, 1996 | EF1 | 70 km | 0.2 mi | 0 |
| Jan 14, 1995 | EF1 | 94 km | 1.0 mi | 0 |
| Apr 19, 1988 | EF1 | 67 km | 0.2 mi | 0 |
| Jan 14, 1980 | EF1 | 62 km | 0.3 mi | 0 |
| Mar 4, 1978 | EF1 | 33 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 | 82 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 86 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | - | 99 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | - | 117 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | - | - | 75 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
3 volcanoes within 200 km. Closest: Mammoth Mountain (189 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Mammoth Mountain | Lava dome(s) | 3,369 m (11,053 ft) | 1260 | 189 km |
| Mono-Inyo Craters | Lava dome(s) | 2,796 m (9,173 ft) | 1380 | 191 km |
| Mono Lake Volcanic Field | Pyroclastic cone(s) | 2,121 m (6,959 ft) | 1790 | 195 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 | 29 km |
| 2017 | DETWILER | 83,297 | 93 km |
| 2015 | BUTTE | 72,894 | 94 km |
| 2007 | LICK | 47,424 | 44 km |
| 2006 | CANYON | 36,851 | 27 km |
| 1992 | GULCH | 18,019 | 92 km |
| 2003 | ANNIE | 17,383 | 38 km |
| 1996 | MERCY | 16,993 | 84 km |
| 2024 | CORRAL | 16,138 | 26 km |
| 2018 | WAVERLY | 12,238 | 57 km |
| 1984 | BONANZA | 12,105 | 93 km |
| 2009 | CORRAL | 12,006 | 27 km |
| 1985 | LEXINGTON | 11,550 | 80 km |
| 2001 | CREEK | 9,793 | 86 km |
| 1992 | MOCCASIN | 9,565 | 83 km |
| 2000 | HUNTER | 7,734 | 89 km |
| 2003 | BIRD | 7,727 | 14 km |
| 1985 | PONOCHE 2 | 7,508 | 100 km |
| 1984 | SITE 300 3 | 6,911 | 28 km |
| 2005 | TESLA | 6,638 | 36 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 48°F (9°C) | 2.6 in | Wettest |
| February | 52°F (11°C) | 2.2 in | |
| March | 57°F (14°C) | 1.8 in | |
| April | 61°F (16°C) | 1.0 in | |
| May | 68°F (20°C) | 0.7 in | |
| June | 75°F (24°C) | 0.2 in | |
| July | 79°F (26°C) | 0.0 in | Warmest, Driest |
| August | 78°F (25°C) | 0.0 in | |
| September | 74°F (23°C) | 0.1 in | |
| October | 65°F (18°C) | 0.6 in | |
| November | 55°F (13°C) | 1.1 in | |
| December | 47°F (9°C) | 2.2 in | Coldest |
Grayson has a seasonal temperature swing of 31°F / from 47°F in December to 79°F in July. Total annual precipitation is 12.3 inches, with January being the wettest month (2.6") and July the driest (0.0").