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Weather & Climate in Boulder, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Boulder has a cool climate with an average annual temperature of 43°F (6°C). Winters average 24°F in January while summers reach 65°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 10.8 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 4,906 feet.
Temperature
24°F Jan (-5°C)
65°F Jul (19°C)
| Annual Average | 42.6°F |
| 21% below US avg | |
| January Average | 24°F (-5°C) |
| July Average | 65°F (19°C) |
| Sunny Days | 273 days/yr |
Geography
| Elevation | 4,906 ft (1,495 m) |
| Area | 1.1 sq mi (2.9 km²) |
| Population Density | 1,184/sq mi |
| Coordinates | 46.2358°N, 112.1197°W |
| Timezone | America/Denver |
| County | Jefferson County County |
| Nearest Airport | Helena Regional (HLN) 26 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
528 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 | 80 km | 12 km |
| Jul 26, 2005 | 16 km N of Dillon, Montana | M5.6 | 104 km | 13 km |
| Jul 6, 2017 | 15 km S of Lincoln, Montana | M5.0 | 77 km | 15 km |
| Jul 6, 2017 | 14 km SE of Lincoln, Montana | M4.4 | 76 km | 10 km |
| May 8, 2007 | 8 km NNW of Alder, Montana | M4.4 | 94 km | 14 km |
| Jan 30, 2016 | 19 km E of Lincoln, Montana | M4.3 | 82 km | 2 km |
| Oct 28, 1998 | 18 km S of Whitehall, Montana | M4.3 | 59 km | 5 km |
| Aug 16, 2019 | 4 km NW of Manhattan, Montana | M4.2 | 70 km | 2 km |
| Aug 6, 2019 | 3 km NW of Manhattan, Montana | M4.1 | 71 km | 5 km |
| Apr 8, 2000 | 8 km ENE of Townsend, Montana | M4.1 | 56 km | 5 km |
| Jun 18, 2006 | 6 km S of Pony, Montana | M4.1 | 73 km | 12 km |
| Oct 7, 2024 | 11 km E of Dillon, Montana | M4.1 | 116 km | 17 km |
| Sep 3, 2016 | 16 km S of Whitehall, Montana | M4.0 | 57 km | 8 km |
| Jul 17, 2017 | 12 km ESE of Lincoln, Montana | M4.0 | 80 km | 13 km |
| Nov 10, 2000 | 14 km NE of Townsend, Montana | M4.0 | 60 km | 2 km |
| Jul 6, 2017 | 14 km SSE of Lincoln, Montana | M4.0 | 76 km | 9 km |
| Mar 6, 2009 | 18 km S of Whitehall, Montana | M4.0 | 59 km | 12 km |
| Jul 27, 2005 | 18 km N of Dillon, Montana | M4.0 | 102 km | 5 km |
| Jan 18, 2006 | 18 km NNE of Dillon, Montana | M4.0 | 102 km | 9 km |
| Jun 28, 2000 | 21 km SE of Clinton, Montana | M4.0 | 117 km | 10 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
17 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF1.
| Date | Rating | Distance | Path | Fatalities |
| Jun 28, 1982 | EF1 | 46 km | 0.5 mi | 0 |
| May 29, 1965 | EF1 | 93 km | 0.1 mi | 0 |
| Sep 15, 1997 | EF0 | 57 km | 0.1 mi | 0 |
| Jul 2, 1997 | EF0 | 73 km | 0.1 mi | 0 |
| Jul 2, 1997 | EF0 | 73 km | 0.1 mi | 0 |
| Jun 27, 1997 | EF0 | 39 km | 0.1 mi | 0 |
| Jun 15, 1996 | EF0 | 78 km | 2.0 mi | 0 |
| May 17, 1994 | EF0 | 56 km | 0.1 mi | 0 |
| Jun 21, 1993 | EF0 | 76 km | 0.1 mi | 0 |
| Jun 11, 1993 | EF0 | 42 km | 0.1 mi | 0 |
| Jul 9, 1992 | EF0 | 68 km | 0.1 mi | 0 |
| Jun 29, 1992 | EF0 | 91 km | 0.1 mi | 0 |
| Jun 12, 1992 | EF0 | 43 km | 0.1 mi | 0 |
| Aug 11, 1988 | EF0 | 85 km | 2.0 mi | 0 |
| May 4, 1971 | EF0 | 80 km | 0.5 mi | 0 |
| May 17, 1962 | EF0 | 65 km | 0.1 mi | 0 |
| Jul 22, 1960 | EF0 | 42 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: TOSTON-MAUDLOW (80,383 acres, 2000).
| Year | Name | Acres Burned | Distance |
| 2000 | TOSTON-MAUDLOW | 80,383 | 67 km |
| 2021 | WOODS CREEK | 55,836 | 73 km |
| 2021 | ALDER CREEK | 38,189 | 93 km |
| 1988 | CANYON CREEK | 35,865 | 34 km |
| 1984 | NORTH HILL | 27,162 | 66 km |
| 2000 | CANYON FERRY COMPLEX (CAVE GULCH) | 26,997 | 64 km |
| 2021 | HAYSTACK | 26,118 | 12 km |
| 2007 | MERIWETHER | 18,865 | 75 km |
| 2012 | BEAR TRAP 2 | 14,875 | 80 km |
| 2000 | CANYON FERRY COMPLEX (BUCKSNORT) | 14,843 | 49 km |
| 1990 | BEARTOOTH COMPLEX | 13,462 | 85 km |
| 2000 | BOULDER COMPLEX (HIGH ORE ROAD) | 9,625 | 8 km |
| 1988 | COMBINATION | 8,588 | 99 km |
| 2015 | EUSTIS | 8,469 | 55 km |
| 2015 | COTTONWOOD GULCH | 8,100 | 68 km |
| 2017 | CHINN MA | 7,029 | 97 km |
| 2009 | INDIAN TRAIL | 4,592 | 84 km |
| 2020 | STATE CREEK | 4,549 | 17 km |
| 2012 | PONY | 4,453 | 61 km |
| 2012 | BEAN CANYON | 4,285 | 67 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 24°F (-5°C) | 0.7 in | |
| February | 26°F (-3°C) | 0.4 in | Driest |
| March | 32°F (0°C) | 0.8 in | |
| April | 40°F (4°C) | 0.9 in | |
| May | 48°F (9°C) | 2.1 in | |
| June | 57°F (14°C) | 2.2 in | Wettest |
| July | 65°F (19°C) | 1.4 in | Warmest |
| August | 62°F (17°C) | 1.4 in | |
| September | 53°F (12°C) | 1.3 in | |
| October | 43°F (6°C) | 0.7 in | |
| November | 30°F (-1°C) | 0.6 in | |
| December | 22°F (-6°C) | 0.6 in | Coldest |
Boulder has a seasonal temperature swing of 44°F / from 22°F in December to 65°F in July. Total annual precipitation is 13.0 inches, with June being the wettest month (2.2") and February the driest (0.4").