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Weather & Climate in Mammoth, WY
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Mammoth has a cool climate with an average annual temperature of 41°F (5°C). Winters average 22°F in January while summers reach 65°F in July. The area gets 311 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 14.8 inches (drier than the 38-inch national average). The area receives 71.5 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 34. The city sits at an elevation of 6,042 feet.
Temperature
22°F Jan (-6°C)
65°F Jul (18°C)
| Annual Average | 40.8°F |
| 24% below US avg | |
| January Average | 22°F (-6°C) |
| July Average | 65°F (18°C) |
| Sunny Days | 311 days/yr |
Geography
| Elevation | 6,042 ft (1,842 m) |
| Area | 0.8 sq mi (2.0 km²) |
| Population Density | 63/sq mi |
| Coordinates | 44.9732°N, 110.6929°W |
| Timezone | America/Denver |
| County | Teton County County |
| Nearest Airport | Bozeman Yellowstone International (BZN) 60 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 34.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 70.6 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 42.5 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Relatively Moderate |
| Flood | Very Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Moderate |
| Lightning | Very High |
| Ice Storm | Very Low |
| Drought | Very Low |
| Cold Wave | Very Low |
| Landslide | Relatively Moderate |
| Volcano | Very Low |
| Avalanche | Very High |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
988 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.8.
| Mar 30, 2014 | 22 km S of Mammoth, Wyoming | M4.8 | 22 km | 6 km |
| Apr 9, 2019 | 9 km NE of Lima, Montana | M4.6 | 146 km | 14 km |
| May 8, 2007 | 8 km NNW of Alder, Montana | M4.4 | 122 km | 14 km |
| Apr 5, 2011 | 28 km NNE of Spencer, Idaho | M4.4 | 117 km | 12 km |
| Feb 5, 2006 | 44 km NE of Spencer, Idaho | M4.4 | 98 km | 14 km |
| Jun 16, 2017 | 12 km E of Hebgen Lake Estates, Montana | M4.4 | 34 km | 9 km |
| Jun 13, 2016 | 45 km W of Hebgen Lake Estates, Montana | M4.3 | 89 km | 10 km |
| Aug 21, 2003 | 53 km N of Kelly, Wyoming | M4.3 | 99 km | 6 km |
| Oct 28, 1998 | 18 km S of Whitehall, Montana | M4.3 | 139 km | 5 km |
| May 11, 2022 | 36 km S of Silver Gate, Montana | M4.2 | 64 km | 14 km |
| Nov 24, 2000 | 24 km S of Mammoth, Wyoming | M4.2 | 25 km | 9 km |
| Aug 5, 2010 | 19 km E of Kelly, Wyoming | M4.2 | 150 km | 5 km |
| Aug 23, 1998 | 9 km N of Alta, Wyoming | M4.2 | 129 km | 5 km |
| Aug 16, 2019 | 4 km NW of Manhattan, Montana | M4.2 | 115 km | 2 km |
| Aug 28, 1995 | 62 km NNE of Kelly, Wyoming | M4.2 | 98 km | 8 km |
| Mar 25, 2008 | 35 km S of Silver Gate, Montana | M4.2 | 62 km | 4 km |
| Oct 7, 2024 | 11 km E of Dillon, Montana | M4.1 | 144 km | 17 km |
| Aug 30, 1997 | 25 km WNW of Hebgen Lake Estates, Montana | M4.1 | 65 km | 4 km |
| Jun 18, 2006 | 6 km S of Pony, Montana | M4.1 | 118 km | 12 km |
| Aug 6, 2019 | 3 km NW of Manhattan, Montana | M4.1 | 113 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
3 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF1.
| Date | Rating | Distance | Path | Fatalities |
| Jun 15, 1960 | EF1 | 86 km | 1.3 mi | 0 |
| Jun 29, 1999 | EF0 | 81 km | 0.2 mi | 0 |
| Jul 6, 1993 | EF0 | 94 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Nearby Volcanoes
1 volcano within 200 km. Closest: Yellowstone (60 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Yellowstone | Caldera(s) | 2,805 m (9,203 ft) | -1350 | 60 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: NORTH FORK (563,527 acres, 1988).
| Year | Name | Acres Burned | Distance |
| 1988 | NORTH FORK | 563,527 | 33 km |
| 1988 | CLOVERMIST | 303,427 | 67 km |
| 2006 | DERBY | 200,993 | 98 km |
| 1988 | STORM CREEK | 116,027 | 57 km |
| 2016 | MAPLE | 103,193 | 35 km |
| 1988 | SNAKE | 95,233 | 80 km |
| 1988 | HELLROARING | 77,598 | 31 km |
| 1988 | CLOVER | 34,035 | 59 km |
| 1988 | SHOSHONE | 29,941 | 67 km |
| 2001 | FRIDLEY | 27,575 | 57 km |
| 1988 | REDSHOSHONE COMPLEX | 27,443 | 72 km |
| 2006 | JUNGLE | 23,846 | 66 km |
| 2007 | WH COMPLEX (WICKED CREEK) | 22,195 | 37 km |
| 1988 | RED | 21,341 | 75 km |
| 1988 | FAN | 20,422 | 22 km |
| 1996 | SHEPARD MTN | 17,379 | 90 km |
| 2007 | COLUMBINE 1 | 17,290 | 76 km |
| 2003 | EAST | 17,226 | 64 km |
| 1988 | FALLS | 16,607 | 87 km |
| 2012 | BEAR TRAP 2 | 14,875 | 100 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 22°F (-6°C) | 2.5 in | Wettest |
| February | 17°F (-8°C) | 1.9 in | |
| March | 23°F (-5°C) | 2.0 in | |
| April | 30°F (-1°C) | 1.7 in | |
| May | 40°F (4°C) | 2.4 in | |
| June | 48°F (9°C) | 2.5 in | |
| July | 65°F (18°C) | 1.7 in | Warmest |
| August | 55°F (13°C) | 1.7 in | |
| September | 47°F (8°C) | 1.8 in | |
| October | 38°F (3°C) | 1.5 in | Driest |
| November | 24°F (-5°C) | 2.2 in | |
| December | 15°F (-9°C) | 2.5 in | Coldest |
Mammoth has a seasonal temperature swing of 50°F / from 15°F in December to 65°F in July. Total annual precipitation is 24.3 inches, with January being the wettest month (2.5") and October the driest (1.5").