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Weather & Climate in St. Marie, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
St. Marie has a cool climate with an average annual temperature of 44°F (7°C). Winters average 14°F in January while summers reach 72°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 2,728 feet.
Temperature
14°F Jan (-10°C)
72°F Jul (22°C)
| Annual Average | 44.3°F |
| 18% below US avg | |
| January Average | 14°F (-10°C) |
| July Average | 72°F (22°C) |
| Sunny Days | 200 days/yr |
Geography
| Elevation | 2,728 ft (831 m) |
| Area | 22.9 sq mi (59.3 km²) |
| Population Density | 14/sq mi |
| Coordinates | 48.4053°N, 106.4986°W |
| Timezone | America/Denver |
| County | Valley County County |
| Nearest Airport | Sidney-Richland Regional (SDY) 117 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 26.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 35.9 / 100 |
| Social Vulnerability | 40.2 / 100 |
| Community Resilience | 45.3 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Moderate |
| Lightning | Very Low |
| Ice Storm | Very Low |
| Drought | Relatively Low |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
4 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.8.
| Feb 25, 2014 | 23 km N of Brockton, Montana | M3.8 | 120 km | 5 km |
| Jul 29, 1998 | 16 km WNW of Froid, Montana | M3.8 | 132 km | 5 km |
| Jul 10, 2021 | 24 km SSE of Malta, Montana | M2.7 | 100 km | 10 km |
| Jul 15, 2015 | 48 km E of Zortman, Montana | M2.5 | 118 km | 23 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
69 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 1 fatality, 1 injury.
| Date | Rating | Distance | Path | Fatalities |
| Jul 18, 2022 | EF2 | 53 km | 8.0 mi | 0 |
| Jul 15, 2013 | EF2 | 66 km | 23.0 mi | 0 |
| Jun 25, 1975 | EF2 | 23 km | 0.1 mi | 0 |
| Jun 25, 1975 | EF2 | 38 km | 0.1 mi | 0 |
| Jun 11, 1972 | EF2 | 31 km | 0.3 mi | 0 |
| Aug 4, 1962 | EF2 | 33 km | 42.9 mi | 0 |
| Jun 29, 2011 | EF1 | 63 km | 0.8 mi | 0 |
| Jun 16, 2010 | EF1 | 55 km | 2.6 mi | 0 |
| Aug 10, 2007 | EF1 | 42 km | 0.3 mi | 0 |
| Aug 10, 2007 | EF1 | 89 km | 0.1 mi | 0 |
| Jun 21, 1999 | EF1 | 50 km | 0.2 mi | 0 |
| Jul 4, 1998 | EF1 | 77 km | 3.0 mi | 0 |
| Jul 4, 1998 | EF1 | 97 km | 2.0 mi | 0 |
| Jul 4, 1991 | EF1 | 78 km | 0.2 mi | 0 |
| Jul 10, 1983 | EF1 | 34 km | 1.0 mi | 0 |
| Jul 9, 1983 | EF1 | 94 km | 1.0 mi | 1 |
| May 25, 1980 | EF1 | 74 km | 0.1 mi | 0 |
| Jun 11, 1972 | EF1 | 64 km | 10.4 mi | 0 |
| Jun 11, 1972 | EF1 | 59 km | 3.6 mi | 0 |
| Aug 6, 1970 | EF1 | 48 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: FLAT TIRE (COMPLEX) (17,467 acres, 2006).
| Year | Name | Acres Burned | Distance |
| 2006 | FLAT TIRE (COMPLEX) | 17,467 | 85 km |
| 2006 | BLACK PULASKI (BLACK PULASKI COMPLEX) | 15,504 | 85 km |
| 2012 | HIGHWAY 13-20 | 8,372 | 86 km |
| 2018 | BUFFALO PASTURE | 7,624 | 91 km |
| 2003 | GREYBULL | 7,229 | 79 km |
| 2017 | LOWER BLACK COULEE | 6,803 | 92 km |
| 2006 | LARB CREEK | 6,778 | 78 km |
| 1988 | LANGEN | 6,585 | 27 km |
| 2007 | BLACK COULEE | 5,613 | 97 km |
| 2006 | BUFFALO RANCH | 5,206 | 87 km |
| 1995 | GRANT COUL | 3,690 | 76 km |
| 2020 | BULL | 3,428 | 65 km |
| 2022 | BLISTER | 3,298 | 76 km |
| 2020 | HILL | 3,175 | 71 km |
| 2001 | CASTLE | 3,021 | 94 km |
| 1999 | HALLOWEEN | 2,845 | 82 km |
| 2021 | BADGER HOLE | 2,804 | 60 km |
| 2020 | SAGE | 2,554 | 48 km |
| 2008 | EAST UNIT CHARLIE | 1,911 | 83 km |
| 2017 | TRIPLE CROSSING | 1,804 | 91 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 14°F (-10°C) | 0.3 in | Coldest |
| February | 19°F (-7°C) | 0.2 in | Driest |
| March | 31°F (-1°C) | 0.4 in | |
| April | 44°F (7°C) | 0.8 in | |
| May | 56°F (13°C) | 1.9 in | |
| June | 65°F (19°C) | 2.3 in | Wettest |
| July | 72°F (22°C) | 1.9 in | Warmest |
| August | 70°F (21°C) | 1.3 in | |
| September | 58°F (14°C) | 1.1 in | |
| October | 46°F (8°C) | 0.6 in | |
| November | 28°F (-2°C) | 0.3 in | |
| December | 15°F (-10°C) | 0.3 in |
St. Marie has a seasonal temperature swing of 58°F / from 14°F in January to 72°F in July. Total annual precipitation is 11.3 inches, with June being the wettest month (2.3") and February the driest (0.2").