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Weather & Climate in Alta, WY
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Alta has a cool climate with an average annual temperature of 41°F (5°C). Winters average 20°F in January while summers reach 64°F in July. The area gets 291 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 25.0 inches (drier than the 38-inch national average). The area receives 113.4 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 6,447 feet.
Temperature
20°F Jan (-6°C)
64°F Jul (18°C)
| Annual Average | 40.5°F |
| 25% below US avg | |
| January Average | 20°F (-6°C) |
| July Average | 64°F (18°C) |
| Sunny Days | 291 days/yr |
Geography
| Elevation | 6,447 ft (1,965 m) |
| Area | 8.3 sq mi (21.6 km²) |
| Population Density | 79/sq mi |
| Coordinates | 43.7736°N, 111.0313°W |
| Timezone | America/Denver |
| County | Teton County County |
| Nearest Airport | Jackson Hole (JAC) 19 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 34.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 29.5 / 100 |
| Social Vulnerability | 13.4 / 100 |
| Community Resilience | 23.1 / 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 | Relatively Moderate |
| Ice Storm | Very Low |
| Drought | Very Low |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
| Volcano | Very Low |
| Avalanche | Relatively High |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
1,984 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.8.
| Feb 3, 1994 | 4 km SSE of Auburn, Wyoming | M5.8 | 113 km | 8 km |
| Apr 21, 2001 | 29 km WSW of Freedom, Idaho | M5.3 | 99 km | 1 km |
| Sep 2, 2017 | 12 km E of Soda Springs, Idaho | M5.3 | 130 km | 10 km |
| Jan 7, 2004 | 20 km ESE of Kelly, Wyoming | M5.0 | 57 km | 3 km |
| Sep 10, 2017 | 9 km NNW of Georgetown, Idaho | M5.0 | 138 km | 10 km |
| Mar 30, 2014 | 22 km S of Mammoth, Wyoming | M4.8 | 114 km | 6 km |
| Aug 5, 2010 | 19 km E of Kelly, Wyoming | M4.8 | 55 km | 5 km |
| Feb 11, 1994 | 3 km SSE of Auburn, Wyoming | M4.8 | 112 km | 5 km |
| Aug 27, 2016 | 4 km ENE of Bondurant, Wyoming | M4.8 | 82 km | 12 km |
| Dec 28, 1993 | 38 km NE of Bondurant, Wyoming | M4.7 | 79 km | 8 km |
| Sep 11, 2017 | 9 km NW of Georgetown, Idaho | M4.7 | 140 km | 8 km |
| Sep 3, 2017 | 10 km E of Soda Springs, Idaho | M4.7 | 131 km | 8 km |
| Sep 10, 2017 | 12 km ESE of Soda Springs, Idaho | M4.7 | 135 km | 5 km |
| Sep 3, 2017 | 15 km ESE of Soda Springs, Idaho | M4.7 | 133 km | 10 km |
| Feb 4, 1994 | 4 km WNW of Fairview, Wyoming | M4.7 | 118 km | 5 km |
| Sep 6, 2017 | 11 km NNW of Georgetown, Idaho | M4.6 | 138 km | 10 km |
| Sep 4, 2017 | 13 km ESE of Soda Springs, Idaho | M4.5 | 133 km | 6 km |
| Feb 7, 1994 | 4 km SW of Fairview, Wyoming | M4.5 | 124 km | 5 km |
| Nov 10, 1992 | 32 km WNW of Freedom, Idaho | M4.4 | 82 km | 10 km |
| Feb 3, 1994 | 2 km SW of Auburn, Wyoming | M4.4 | 111 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
35 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 1 injury.
| Date | Rating | Distance | Path | Fatalities |
| Jul 21, 1987 | EF4 | 58 km | 24.3 mi | 0 |
| Jun 12, 2022 | EF2 | 46 km | 2.1 mi | 0 |
| Apr 7, 1978 | EF2 | 86 km | 1.5 mi | 0 |
| Sep 26, 1959 | EF2 | 71 km | 1.0 mi | 0 |
| Jun 1, 2002 | EF1 | 90 km | 2.5 mi | 0 |
| Feb 14, 2000 | EF1 | 100 km | 12.0 mi | 0 |
| Jun 2, 1992 | EF1 | 81 km | 0.5 mi | 0 |
| Jun 4, 1991 | EF1 | 62 km | 0.2 mi | 0 |
| Apr 17, 1988 | EF1 | 89 km | 2.0 mi | 0 |
| Apr 17, 1988 | EF1 | 62 km | 0.5 mi | 0 |
| Mar 23, 1988 | EF1 | 88 km | 15.0 mi | 0 |
| Apr 11, 1985 | EF1 | 77 km | 0.1 mi | 0 |
| May 15, 1984 | EF1 | 56 km | 8.0 mi | 0 |
| Apr 21, 1981 | EF1 | 77 km | 1.1 mi | 0 |
| Jul 8, 1980 | EF1 | 63 km | 0.1 mi | 0 |
| Jun 20, 1977 | EF1 | 98 km | 2.0 mi | 0 |
| Mar 13, 1959 | EF1 | 96 km | 0.4 mi | 0 |
| Aug 25, 1955 | EF1 | 70 km | 0.5 mi | 0 |
| Jun 2, 2019 | EF0 | 85 km | 1.0 mi | 0 |
| Nov 17, 2017 | EF0 | 69 km | 5.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Nearby Volcanoes
2 volcanoes within 200 km. Closest: Yellowstone (79 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Yellowstone | Caldera(s) | 2,805 m (9,203 ft) | -1350 | 79 km |
| Hell's Half Acre | Shield | 1,631 m (5,351 ft) | -3250 | 118 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: MINK (135,433 acres, 1988).
| Year | Name | Acres Burned | Distance |
| 1988 | MINK | 135,433 | 88 km |
| 1988 | HUCK | 123,437 | 57 km |
| 2018 | GRASSY RIDGE | 106,164 | 88 km |
| 1988 | SNAKE | 95,233 | 74 km |
| 2018 | ROOSEVELT | 55,330 | 95 km |
| 2016 | HENRYS CREEK | 52,988 | 69 km |
| 2016 | CLIFF CREEK | 36,131 | 75 km |
| 1988 | SHOSHONE | 29,941 | 78 km |
| 2012 | NORTH BUFFALO | 28,324 | 75 km |
| 1988 | REDSHOSHONE COMPLEX | 27,443 | 76 km |
| 1988 | RED | 21,341 | 70 km |
| 2016 | BERRY | 20,783 | 39 km |
| 2006 | PURDY | 18,653 | 83 km |
| 2017 | DEER PARK | 17,745 | 82 km |
| 1988 | FALLS | 16,607 | 53 km |
| 2016 | LAVA MOUNTAIN | 14,652 | 93 km |
| 2006 | SNOWSHOE | 11,910 | 86 km |
| 2003 | MENAN | 11,790 | 79 km |
| 2009 | ARNICA | 10,738 | 92 km |
| 2011 | RED ROCK COMPLEX | 10,046 | 62 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-6°C) | 2.4 in | |
| February | 21°F (-6°C) | 1.8 in | |
| March | 28°F (-2°C) | 1.8 in | |
| April | 37°F (3°C) | 1.9 in | |
| May | 46°F (8°C) | 3.1 in | Wettest |
| June | 55°F (13°C) | 2.1 in | |
| July | 64°F (18°C) | 1.5 in | Warmest |
| August | 61°F (16°C) | 1.5 in | Driest |
| September | 52°F (11°C) | 1.7 in | |
| October | 42°F (5°C) | 1.8 in | |
| November | 28°F (-2°C) | 2.1 in | |
| December | 18°F (-8°C) | 2.1 in | Coldest |
Alta has a seasonal temperature swing of 46°F / from 18°F in December to 64°F in July. Total annual precipitation is 23.8 inches, with May being the wettest month (3.1") and August the driest (1.5").