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Weather & Climate in Big Sandy, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Big Sandy has a cool climate with an average annual temperature of 45°F (7°C). Winters average 20°F in January while summers reach 70°F in July. The area gets 274 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 13.3 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 26 / among the cleanest air in the country. The city sits at an elevation of 2,702 feet.
Temperature
20°F Jan (-7°C)
70°F Jul (21°C)
| Annual Average | 45.1°F |
| 16% below US avg | |
| January Average | 20°F (-7°C) |
| July Average | 70°F (21°C) |
| Sunny Days | 274 days/yr |
Geography
| Elevation | 2,702 ft (824 m) |
| Area | 0.5 sq mi (1.2 km²) |
| Population Density | 1,758/sq mi |
| Coordinates | 48.1786°N, 110.1133°W |
| Timezone | America/Denver |
| County | Hill County County |
| Nearest Airport | Great Falls International (GTF) 76 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 26.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 50.5 / 100 |
| Social Vulnerability | 67.1 / 100 |
| Community Resilience | 38.1 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively High |
| Lightning | Relatively Moderate |
| Ice Storm | Very Low |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
5 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.9.
| Aug 16, 1994 | 27 km W of Chester, Montana | M3.9 | 97 km | 5 km |
| Jun 5, 1991 | 18 km SW of Shelby, Montana | M3.6 | 142 km | 5 km |
| Apr 2, 2014 | 13 km NNW of Conrad, Montana | M3.1 | 142 km | 7 km |
| Dec 5, 1991 | 15 km WSW of Hays, Montana | M3.0 | 94 km | 10 km |
| Feb 25, 2013 | 28 km WSW of Chester, Montana | M2.5 | 91 km | 18 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
38 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 7 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jul 5, 1988 | EF3 | 55 km | 3.0 mi | 0 |
| Jul 5, 1988 | EF3 | 25 km | 12.0 mi | 0 |
| Jul 5, 1988 | EF3 | 37 km | 10.0 mi | 0 |
| Jun 25, 1996 | EF2 | 90 km | 2.0 mi | 0 |
| Jun 8, 1976 | EF2 | 92 km | 0.1 mi | 0 |
| Jul 8, 2002 | EF1 | 79 km | 2.0 mi | 0 |
| Jun 19, 1998 | EF1 | 72 km | 1.0 mi | 0 |
| Jun 16, 1995 | EF1 | 89 km | 0.1 mi | 0 |
| Jun 1, 1980 | EF1 | 76 km | 0.1 mi | 0 |
| May 25, 1980 | EF1 | 45 km | 0.1 mi | 0 |
| May 25, 1980 | EF1 | 77 km | 0.1 mi | 0 |
| May 24, 1977 | EF1 | 65 km | 0.1 mi | 0 |
| Jul 10, 1965 | EF1 | 66 km | 0.2 mi | 0 |
| Jul 1, 1962 | EF1 | 43 km | 3.8 mi | 0 |
| Jun 29, 1960 | EF1 | 91 km | 0.3 mi | 0 |
| Aug 26, 2022 | EF0 | 87 km | 3.1 mi | 0 |
| Jun 23, 2018 | EF0 | 80 km | 1.4 mi | 0 |
| Jun 13, 2014 | EF0 | 71 km | 0.3 mi | 0 |
| Jun 5, 2012 | EF0 | 27 km | 1.1 mi | 0 |
| Jun 17, 2005 | EF0 | 75 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: BLAINE C (138,192 acres, 1991).
| Year | Name | Acres Burned | Distance |
| 1991 | BLAINE C | 138,192 | 71 km |
| 2021 | TAYLOR | 21,704 | 84 km |
| 2017 | EAST FORK | 21,165 | 40 km |
| 2009 | MEISSNER | 12,318 | 83 km |
| 1984 | CENTENNIAL | 11,775 | 26 km |
| 2006 | MAGGIE | 8,187 | 93 km |
| 2022 | EAGLE CREEK | 6,359 | 36 km |
| 1988 | LOSTCANYON | 4,532 | 24 km |
| 2008 | CHOUTEAU CO COMPLEX | 4,365 | 34 km |
| 2003 | LAKE17 | 4,054 | 96 km |
| 2012 | OUTHOUSE | 3,179 | 63 km |
| 2007 | CHOUTEAU CO ASST | 2,646 | 55 km |
| 2014 | 2 RAINTRAP PASTURE PRESCRIBED FIRE | 2,311 | 86 km |
| 2021 | FOUR SISTERS | 1,999 | 74 km |
| 2011 | WILD HORSE | 1,882 | 96 km |
| 2021 | EAGLE BUTTE | 1,817 | 38 km |
| 2013 | PEOPLES CREEK | 1,623 | 98 km |
| 1988 | P N | 1,533 | 62 km |
| 2012 | BIG STRETCH | 1,524 | 34 km |
| 1984 | FRITZ | 1,491 | 66 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-7°C) | 0.6 in | Coldest |
| February | 21°F (-6°C) | 0.4 in | Driest |
| March | 33°F (0°C) | 0.6 in | |
| April | 44°F (7°C) | 1.0 in | |
| May | 54°F (12°C) | 2.5 in | Wettest |
| June | 63°F (17°C) | 2.3 in | |
| July | 70°F (21°C) | 1.5 in | Warmest |
| August | 68°F (20°C) | 1.4 in | |
| September | 57°F (14°C) | 1.4 in | |
| October | 46°F (8°C) | 0.7 in | |
| November | 31°F (-1°C) | 0.4 in | |
| December | 21°F (-6°C) | 0.6 in |
Big Sandy has a seasonal temperature swing of 50°F / from 20°F in January to 70°F in July. Total annual precipitation is 13.3 inches, with May being the wettest month (2.5") and February the driest (0.4").