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Weather & Climate in Sweet Grass, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Sweet Grass has a cool climate with an average annual temperature of 44°F (6°C). Winters average 21°F in January while summers reach 68°F in July. The area gets 200 sunny days per year. 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 3,552 feet.
Temperature
21°F Jan (-6°C)
68°F Jul (20°C)
| Annual Average | 43.5°F |
| 19% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 68°F (20°C) |
| Sunny Days | 200 days/yr |
Geography
| Elevation | 3,552 ft (1,083 m) |
| Area | 0.5 sq mi (1.2 km²) |
| Population Density | 133/sq mi |
| Coordinates | 48.9928°N, 111.9668°W |
| Timezone | America/Denver |
| County | Toole County County |
| Nearest Airport | Cut Bank International (CTB) 32 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 26.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 13.0 / 100 |
| Social Vulnerability | 64.7 / 100 |
| Community Resilience | 19.8 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Very Low |
| Drought | Relatively Low |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
30 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 | 73 km | 5 km |
| May 1, 1997 | 35 km SSE of Magrath, Canada | M3.8 | 52 km | 5 km |
| Jul 2, 1992 | 4 km SSE of South Browning, Montana | M3.8 | 93 km | 10 km |
| Jun 5, 1991 | 18 km SW of Shelby, Montana | M3.6 | 69 km | 5 km |
| Sep 29, 2009 | 42 km NW of Santa Rita, Montana | M3.6 | 49 km | 21 km |
| May 10, 1990 | 47 km SSW of Heart Butte, Montana | M3.6 | 147 km | 5 km |
| Jan 3, 2008 | 13 km SSE of Magrath, Canada | M3.5 | 69 km | 38 km |
| Jan 20, 2003 | 10 km S of Little Browning, Montana | M3.5 | 58 km | 1 km |
| Jan 1, 1993 | 20 km WSW of Sweet Grass, Montana | M3.4 | 20 km | 5 km |
| Sep 7, 2014 | 36 km SSE of Magrath, Canada | M3.4 | 52 km | 15 km |
| Nov 21, 1992 | Western Montana | M3.4 | 126 km | 5 km |
| Nov 17, 1992 | 39 km NNW of Santa Rita, Montana | M3.4 | 47 km | 5 km |
| Aug 15, 1996 | 33 km WNW of Sweet Grass, Montana | M3.4 | 33 km | 5 km |
| Jan 22, 1993 | 33 km SSE of Raymond, Canada | M3.4 | 40 km | 5 km |
| Nov 6, 2002 | 3 km SSE of Little Browning, Montana | M3.4 | 51 km | 1 km |
| Mar 5, 1995 | 2 km NW of Cut Bank, Montana | M3.3 | 47 km | 10 km |
| Jan 11, 2003 | 44 km SSE of Magrath, Canada | M3.2 | 52 km | 10 km |
| May 29, 2009 | 11 km S of Little Browning, Montana | M3.2 | 59 km | 0 km |
| Apr 2, 2014 | 13 km NNW of Conrad, Montana | M3.1 | 80 km | 7 km |
| Apr 4, 1990 | 4 km WNW of Santa Rita, Montana | M3.1 | 43 km | 6 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
14 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2.
| Date | Rating | Distance | Path | Fatalities |
| May 7, 1982 | EF2 | 11 km | 0.5 mi | 0 |
| Jun 13, 2006 | EF1 | 64 km | 10.0 mi | 0 |
| Jun 6, 1994 | EF1 | 43 km | 0.1 mi | 0 |
| May 25, 1980 | EF1 | 86 km | 0.1 mi | 0 |
| Jun 1, 1977 | EF1 | 44 km | 0.1 mi | 0 |
| May 24, 1977 | EF1 | 100 km | 0.1 mi | 0 |
| Jun 27, 1996 | EF0 | 89 km | 0.2 mi | 0 |
| Jun 6, 1994 | EF0 | 47 km | 0.1 mi | 0 |
| Jun 21, 1993 | EF0 | 56 km | 0.1 mi | 0 |
| Aug 3, 1992 | EF0 | 94 km | 0.1 mi | 0 |
| Jun 29, 1991 | EF0 | 22 km | 0.2 mi | 0 |
| May 7, 1982 | EF0 | 11 km | 0.1 mi | 0 |
| Aug 2, 1981 | EF0 | 52 km | 0.1 mi | 0 |
| Aug 2, 1981 | EF0 | 52 km | 0.1 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
9 wildfires (100+ acres) recorded within 100 km. Largest: GREENHOUSE (14,501 acres, 2021).
| Year | Name | Acres Burned | Distance |
| 2021 | GREENHOUSE | 14,501 | 78 km |
| 2012 | WYE FIRE | 6,141 | 79 km |
| 2012 | BOY | 5,706 | 81 km |
| 1996 | SHARPSFIRE | 4,461 | 81 km |
| 2003 | PARDUE | 4,269 | 60 km |
| 2017 | WOLVERINE | 3,126 | 96 km |
| 1992 | RDOORECMPX | 3,088 | 84 km |
| 1994 | WALBERGERS | 1,732 | 87 km |
| 2006 | MISSION LAKE FIRE | 1,100 | 69 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 21°F (-6°C) | 0.4 in | Coldest |
| February | 25°F (-4°C) | 0.3 in | Driest |
| March | 33°F (1°C) | 0.6 in | |
| April | 44°F (7°C) | 0.9 in | |
| May | 53°F (12°C) | 2.4 in | |
| June | 61°F (16°C) | 2.7 in | Wettest |
| July | 68°F (20°C) | 1.4 in | Warmest |
| August | 66°F (19°C) | 1.6 in | |
| September | 56°F (13°C) | 1.3 in | |
| October | 45°F (7°C) | 0.6 in | |
| November | 31°F (-1°C) | 0.4 in | |
| December | 22°F (-6°C) | 0.4 in |
Sweet Grass has a seasonal temperature swing of 46°F / from 21°F in January to 68°F in July. Total annual precipitation is 13.1 inches, with June being the wettest month (2.7") and February the driest (0.3").