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Weather & Climate in Chinook, MT
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Chinook has a cool climate with an average annual temperature of 42°F (6°C). Winters average 16°F in January while summers reach 69°F in July. The area gets 274 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). 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 2,424 feet.
Temperature
16°F Jan (-9°C)
69°F Jul (21°C)
| Annual Average | 42.4°F |
| 21% below US avg | |
| January Average | 16°F (-9°C) |
| July Average | 69°F (21°C) |
| Sunny Days | 274 days/yr |
Geography
| Elevation | 2,424 ft (739 m) |
| Area | 0.5 sq mi (1.3 km²) |
| Population Density | 2,808/sq mi |
| Coordinates | 48.5901°N, 109.2318°W |
| Timezone | America/Denver |
| County | Blaine County County |
| Nearest Airport | Great Falls International (GTF) 125 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 26.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 45.9 / 100 |
| Social Vulnerability | 95.7 / 100 |
| Community Resilience | 13.4 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Very Low |
| Wildfire | Relatively Low |
| Flood | Relatively Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Moderate |
| Ice Storm | Very Low |
| Drought | Relatively Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
| Avalanche | 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: M3.0.
| Dec 5, 1991 | 15 km WSW of Hays, Montana | M3.0 | 75 km | 10 km |
| Oct 16, 2011 | Eastern Montana | M2.7 | 145 km | 21 km |
| Jul 10, 2021 | 24 km SSE of Malta, Montana | M2.7 | 117 km | 10 km |
| Jul 15, 2015 | 48 km E of Zortman, Montana | M2.5 | 128 km | 23 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
20 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3.
| Date | Rating | Distance | Path | Fatalities |
| Jul 5, 1988 | EF3 | 95 km | 10.0 mi | 0 |
| Jul 5, 1988 | EF3 | 88 km | 12.0 mi | 0 |
| Jul 8, 2002 | EF1 | 1 km | 2.0 mi | 0 |
| Jun 16, 1995 | EF1 | 90 km | 0.1 mi | 0 |
| May 25, 1980 | EF1 | 88 km | 0.1 mi | 0 |
| Jul 1, 1962 | EF1 | 43 km | 3.8 mi | 0 |
| Aug 26, 2022 | EF0 | 37 km | 3.1 mi | 0 |
| Jul 31, 2014 | EF0 | 65 km | 0.1 mi | 0 |
| Jun 13, 2014 | EF0 | 18 km | 0.3 mi | 0 |
| Jun 5, 2012 | EF0 | 75 km | 1.1 mi | 0 |
| Jun 20, 2005 | EF0 | 50 km | 0.1 mi | 0 |
| Jun 17, 2005 | EF0 | 97 km | 0.1 mi | 0 |
| Jun 18, 1999 | EF0 | 1 km | 0.5 mi | 0 |
| Jun 26, 1994 | EF0 | 73 km | 0.1 mi | 0 |
| Jun 26, 1994 | EF0 | 74 km | 0.1 mi | 0 |
| Aug 16, 1993 | EF0 | 50 km | 0.1 mi | 0 |
| Jul 20, 1993 | EF0 | 89 km | 0.1 mi | 0 |
| Jun 6, 1986 | EF0 | 54 km | 0.2 mi | 0 |
| Jun 30, 1979 | EF0 | 94 km | 0.1 mi | 0 |
| Jun 28, 1971 | EF0 | 73 km | 2.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: BLAINE C (138,192 acres, 1991).
| Year | Name | Acres Burned | Distance |
| 1991 | BLAINE C | 138,192 | 23 km |
| 2012 | WELDER | 32,985 | 60 km |
| 1990 | VETERANS | 23,660 | 81 km |
| 2017 | EAST FORK | 21,165 | 47 km |
| 2021 | PINE GROVE | 16,158 | 81 km |
| 1984 | CENTENNIAL | 11,775 | 56 km |
| 2017 | JULY | 11,409 | 92 km |
| 2006 | MAGGIE | 8,187 | 42 km |
| 2022 | EAGLE CREEK | 6,359 | 57 km |
| 1988 | MONUMENT | 5,514 | 85 km |
| 1988 | LOSTCANYON | 4,532 | 60 km |
| 2003 | LAKE17 | 4,054 | 61 km |
| 2008 | KATHRYN | 3,971 | 83 km |
| 2006 | HOWARD | 3,884 | 55 km |
| 2014 | MIDDLE BLACK | 3,854 | 40 km |
| 2012 | OUTHOUSE | 3,179 | 22 km |
| 1990 | ADAMS | 3,072 | 68 km |
| 1990 | QUISNO | 3,018 | 58 km |
| 2014 | 2 RAINTRAP PASTURE PRESCRIBED FIRE | 2,311 | 70 km |
| 1997 | HERD | 2,259 | 75 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 16°F (-9°C) | 0.6 in | Coldest |
| February | 21°F (-6°C) | 0.4 in | Driest |
| March | 32°F (-0°C) | 0.6 in | |
| April | 44°F (7°C) | 1.1 in | |
| May | 54°F (12°C) | 2.2 in | |
| June | 63°F (17°C) | 2.3 in | Wettest |
| July | 69°F (21°C) | 1.7 in | Warmest |
| August | 68°F (20°C) | 1.3 in | |
| September | 57°F (14°C) | 1.4 in | |
| October | 45°F (7°C) | 0.6 in | |
| November | 29°F (-2°C) | 0.5 in | |
| December | 18°F (-8°C) | 0.5 in |
Chinook has a seasonal temperature swing of 53°F / from 16°F in January to 69°F in July. Total annual precipitation is 13.1 inches, with June being the wettest month (2.3") and February the driest (0.4").