All Countries
Weather & Climate in Unionville, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Unionville has a cool climate with an average annual temperature of 40°F (5°C). Winters average 21°F in January while summers reach 64°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 16.5 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 5,060 feet.
Temperature
21°F Jan (-6°C)
64°F Jul (18°C)
| Annual Average | 40.3°F |
| 25% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 64°F (18°C) |
| Sunny Days | 273 days/yr |
Geography
| Elevation | 5,060 ft (1,542 m) |
| Area | 1.3 sq mi (3.3 km²) |
| Population Density | 302/sq mi |
| Coordinates | 46.5464°N, 112.0852°W |
| Timezone | America/Denver |
| County | Jefferson County County |
| Nearest Airport | Helena Regional (HLN) 6 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 26.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 21.6 / 100 |
| Social Vulnerability | 24.0 / 100 |
| Community Resilience | 34.4 / 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 Moderate |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
494 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.8.
| Jul 6, 2017 | 11 km SE of Lincoln, Montana | M5.8 | 53 km | 12 km |
| Jul 26, 2005 | 16 km N of Dillon, Montana | M5.6 | 138 km | 13 km |
| Jul 6, 2017 | 15 km S of Lincoln, Montana | M5.0 | 53 km | 15 km |
| Jul 6, 2017 | 14 km SE of Lincoln, Montana | M4.4 | 49 km | 10 km |
| May 8, 2007 | 8 km NNW of Alder, Montana | M4.4 | 128 km | 14 km |
| Jan 30, 2016 | 19 km E of Lincoln, Montana | M4.3 | 51 km | 2 km |
| Oct 28, 1998 | 18 km S of Whitehall, Montana | M4.3 | 94 km | 5 km |
| Aug 16, 2019 | 4 km NW of Manhattan, Montana | M4.2 | 92 km | 2 km |
| Oct 7, 2024 | 11 km E of Dillon, Montana | M4.1 | 150 km | 17 km |
| Jun 18, 2006 | 6 km S of Pony, Montana | M4.1 | 106 km | 12 km |
| Apr 8, 2000 | 8 km ENE of Townsend, Montana | M4.1 | 57 km | 5 km |
| Aug 6, 2019 | 3 km NW of Manhattan, Montana | M4.1 | 93 km | 5 km |
| Sep 3, 2016 | 16 km S of Whitehall, Montana | M4.0 | 91 km | 8 km |
| Jul 27, 2005 | 18 km N of Dillon, Montana | M4.0 | 136 km | 5 km |
| Jan 18, 2006 | 18 km NNE of Dillon, Montana | M4.0 | 136 km | 9 km |
| Mar 6, 2009 | 18 km S of Whitehall, Montana | M4.0 | 94 km | 12 km |
| Jul 6, 2017 | 14 km SSE of Lincoln, Montana | M4.0 | 50 km | 9 km |
| Jun 28, 2000 | 21 km SE of Clinton, Montana | M4.0 | 111 km | 10 km |
| Jul 17, 2017 | 12 km ESE of Lincoln, Montana | M4.0 | 52 km | 13 km |
| Jul 19, 2002 | 43 km NE of Seeley Lake, Montana | M4.0 | 123 km | 25 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
21 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2.
| Date | Rating | Distance | Path | Fatalities |
| Jun 30, 1975 | EF2 | 82 km | 0.1 mi | 0 |
| Jun 5, 2012 | EF1 | 94 km | 2.8 mi | 0 |
| Jun 28, 1982 | EF1 | 48 km | 0.5 mi | 0 |
| Jul 3, 1978 | EF1 | 98 km | 1.0 mi | 0 |
| Jul 3, 1978 | EF1 | 98 km | 1.0 mi | 0 |
| Jul 3, 1978 | EF1 | 98 km | 1.0 mi | 0 |
| Sep 15, 1997 | EF0 | 76 km | 0.1 mi | 0 |
| Jul 2, 1997 | EF0 | 94 km | 0.1 mi | 0 |
| Jul 2, 1997 | EF0 | 94 km | 0.1 mi | 0 |
| Jun 27, 1997 | EF0 | 6 km | 0.1 mi | 0 |
| Jun 15, 1996 | EF0 | 75 km | 2.0 mi | 0 |
| May 17, 1994 | EF0 | 79 km | 0.1 mi | 0 |
| Jun 21, 1993 | EF0 | 42 km | 0.1 mi | 0 |
| Jun 11, 1993 | EF0 | 10 km | 0.1 mi | 0 |
| Jul 9, 1992 | EF0 | 38 km | 0.1 mi | 0 |
| Jun 12, 1992 | EF0 | 47 km | 0.1 mi | 0 |
| Aug 11, 1988 | EF0 | 87 km | 2.0 mi | 0 |
| May 4, 1971 | EF0 | 69 km | 0.5 mi | 0 |
| May 17, 1962 | EF0 | 65 km | 0.1 mi | 0 |
| Jul 22, 1960 | EF0 | 9 km | 1.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: CANYON CREEK (167,875 acres, 1988).
| Year | Name | Acres Burned | Distance |
| 1988 | CANYON CREEK | 167,875 | 92 km |
| 2000 | TOSTON-MAUDLOW | 80,383 | 74 km |
| 2021 | WOODS CREEK | 55,836 | 62 km |
| 2003 | LINCOLN COMPLEX (SNOWBANK) | 36,987 | 73 km |
| 1988 | CANYON CREEK | 35,865 | 25 km |
| 2021 | HARRIS MTN | 31,792 | 70 km |
| 2017 | ALICE CREEK | 29,971 | 72 km |
| 1984 | NORTH HILL | 27,162 | 32 km |
| 2000 | CANYON FERRY COMPLEX (CAVE GULCH) | 26,997 | 40 km |
| 2021 | HAYSTACK | 26,118 | 45 km |
| 2007 | MERIWETHER | 18,865 | 42 km |
| 2017 | PARK CREEK | 17,915 | 74 km |
| 2000 | CANYON FERRY COMPLEX (BUCKSNORT) | 14,843 | 29 km |
| 1990 | BEARTOOTH COMPLEX | 13,462 | 52 km |
| 2000 | BOULDER COMPLEX (HIGH ORE ROAD) | 9,625 | 28 km |
| 1988 | COMBINATION | 8,588 | 100 km |
| 2015 | EUSTIS | 8,469 | 74 km |
| 2015 | COTTONWOOD GULCH | 8,100 | 88 km |
| 2017 | CHINN MA | 7,029 | 95 km |
| 2009 | INDIAN TRAIL | 4,592 | 50 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 21°F (-6°C) | 0.7 in | Coldest |
| February | 27°F (-3°C) | 0.5 in | Driest |
| March | 34°F (1°C) | 0.7 in | |
| April | 42°F (6°C) | 0.9 in | |
| May | 51°F (10°C) | 1.9 in | |
| June | 59°F (15°C) | 2.0 in | Wettest |
| July | 64°F (18°C) | 1.3 in | |
| August | 65°F (18°C) | 1.4 in | Warmest |
| September | 55°F (13°C) | 1.2 in | |
| October | 45°F (7°C) | 0.7 in | |
| November | 32°F (-0°C) | 0.6 in | |
| December | 23°F (-5°C) | 0.6 in |
Unionville has a seasonal temperature swing of 44°F / from 21°F in January to 65°F in August. Total annual precipitation is 12.4 inches, with June being the wettest month (2.0") and February the driest (0.5").