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Weather & Climate in Fallon, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Fallon has a cool climate with an average annual temperature of 45°F (7°C). Winters average 17°F in January while summers reach 73°F in July. The area gets 273 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 13.4 inches (drier than the 38-inch national average). The area receives 11.8 inches of snow annually. 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 2,203 feet.
Temperature
17°F Jan (-8°C)
73°F Jul (23°C)
| Annual Average | 45.3°F |
| 16% below US avg | |
| January Average | 17°F (-8°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 273 days/yr |
Geography
| Elevation | 2,203 ft (671 m) |
| Area | 5.3 sq mi (13.7 km²) |
| Population Density | 60/sq mi |
| Coordinates | 46.8371°N, 105.1275°W |
| Timezone | America/Denver |
| County | Prairie County County |
| Nearest Airport | Sidney-Richland Regional (SDY) 74 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 26.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 4.2 / 100 |
| Social Vulnerability | 74.1 / 100 |
| Community Resilience | 19.5 / 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 | Very Low |
| Cold Wave | Relatively Low |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
3 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.5.
| Nov 3, 1999 | 8 km NNW of Broadus, Montana | M3.5 | 150 km | 10 km |
| May 6, 2014 | 12 km NNW of Knife River, Montana | M2.6 | 95 km | 8 km |
| Jul 29, 2013 | 18 km SE of Ekalaka, Montana | M2.6 | 132 km | 8 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
62 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 1 fatality, 10 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 29, 1961 | EF4 | 44 km | 15.9 mi | 0 |
| Jun 11, 2016 | EF3 | 89 km | 3.0 mi | 0 |
| May 24, 1953 | EF3 | 74 km | 9.3 mi | 0 |
| Jul 19, 1952 | EF3 | 83 km | 55.5 mi | 0 |
| Jul 19, 1952 | EF3 | 68 km | 16.4 mi | 1 |
| Jun 10, 1952 | EF3 | 89 km | 8.8 mi | 0 |
| Jul 25, 2001 | EF2 | 95 km | 5.0 mi | 0 |
| Jul 25, 2001 | EF2 | 72 km | 2.0 mi | 0 |
| Jun 20, 1999 | EF2 | 80 km | 5.0 mi | 0 |
| Jul 11, 1995 | EF2 | 74 km | 0.5 mi | 0 |
| Jun 27, 1975 | EF2 | 53 km | 0.1 mi | 0 |
| Jun 25, 1975 | EF2 | 74 km | 0.1 mi | 0 |
| Jul 11, 1965 | EF2 | 36 km | 5.4 mi | 0 |
| Jul 18, 1962 | EF2 | 30 km | 40.6 mi | 0 |
| Aug 26, 1954 | EF2 | 90 km | 20.9 mi | 0 |
| Jun 23, 1953 | EF2 | 44 km | 33.5 mi | 0 |
| Jul 8, 2013 | EF1 | 82 km | 0.6 mi | 0 |
| May 20, 2011 | EF1 | 23 km | 0.1 mi | 0 |
| Jul 25, 2001 | EF1 | 85 km | 2.0 mi | 0 |
| Jul 22, 1979 | EF1 | 84 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: OKERMAN (15,478 acres, 2007).
| Year | Name | Acres Burned | Distance |
| 2007 | OKERMAN | 15,478 | 79 km |
| 1990 | KNOWLTON C | 13,226 | 52 km |
| 1998 | BRADSHAW | 10,591 | 42 km |
| 1991 | MEDICINE ROCK | 8,565 | 97 km |
| 2017 | CROW ROCK | 8,298 | 70 km |
| 2008 | KNOWLTON COMPLEX (DRGA) | 7,218 | 57 km |
| 2007 | WOLF CREEK | 7,029 | 87 km |
| 2000 | TOOKE | 6,128 | 97 km |
| 1996 | ROBINSON | 5,901 | 88 km |
| 2015 | HERCULES | 3,482 | 93 km |
| 2003 | 3 MILE | 3,394 | 55 km |
| 2007 | ROCK SPRINGS | 3,094 | 71 km |
| 1996 | FT. KEOGH | 3,018 | 81 km |
| 2021 | GREAT DIVIDE - DAWSON | 3,003 | 55 km |
| 1999 | CEDARCRKN | 2,964 | 41 km |
| 1988 | DEER CRK | 2,711 | 92 km |
| 2021 | DOROTHY DRAW | 2,565 | 47 km |
| 2006 | WOODY | 1,770 | 66 km |
| 2021 | BRACKETT | 1,756 | 38 km |
| 2007 | UNNAMED | 1,748 | 87 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 17°F (-8°C) | 0.4 in | Coldest |
| February | 23°F (-5°C) | 0.3 in | Driest |
| March | 33°F (0°C) | 0.5 in | |
| April | 45°F (7°C) | 1.2 in | |
| May | 56°F (14°C) | 2.1 in | |
| June | 66°F (19°C) | 2.4 in | Wettest |
| July | 73°F (23°C) | 1.7 in | Warmest |
| August | 71°F (22°C) | 1.3 in | |
| September | 59°F (15°C) | 1.3 in | |
| October | 47°F (8°C) | 0.9 in | |
| November | 30°F (-1°C) | 0.4 in | |
| December | 19°F (-7°C) | 0.3 in |
Fallon has a seasonal temperature swing of 56°F / from 17°F in January to 73°F in July. Total annual precipitation is 12.6 inches, with June being the wettest month (2.4") and February the driest (0.3").