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Weather & Climate in Ontonagon, MI
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Ontonagon has a cool climate with an average annual temperature of 43°F (6°C). Winters average 17°F in January while summers reach 67°F in July. The area gets 249 sunny days per year, above the national average. Annual precipitation totals 32.9 inches. The area receives 177.7 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 38. The city sits at an elevation of 642 feet.
Temperature
17°F Jan (-8°C)
67°F Jul (20°C)
| Annual Average | 43.3°F |
| 20% below US avg | |
| January Average | 17°F (-8°C) |
| July Average | 67°F (20°C) |
| Sunny Days | 249 days/yr |
Geography
| Elevation | 642 ft (196 m) |
| Area | 3.9 sq mi (10.0 km²) |
| Population Density | 344/sq mi |
| Coordinates | 46.8663°N, 89.3124°W |
| Timezone | America/Detroit |
| County | Ontonagon County County |
| Nearest Airport | Marquette/Sawyer Regional (MQT) 99 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 38.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 4.2 / 100 |
| Social Vulnerability | 66.2 / 100 |
| Community Resilience | 67.7 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Hurricane | No Rating |
| Earthquake | No Rating |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Very Low |
| Drought | Very Low |
| Cold Wave | Relatively Low |
| Landslide | Very Low |
| Coastal Flood | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tornado History
21 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3.
| Date | Rating | Distance | Path | Fatalities |
| Jul 7, 1970 | EF3 | 85 km | 37.9 mi | 0 |
| Aug 22, 1968 | EF2 | 75 km | 0.3 mi | 0 |
| Jul 14, 1958 | EF2 | 97 km | 1.5 mi | 0 |
| Aug 9, 2020 | EF1 | 94 km | 6.2 mi | 0 |
| Jul 11, 2016 | EF1 | 75 km | 2.4 mi | 0 |
| Jul 11, 2016 | EF1 | 86 km | 2.3 mi | 0 |
| Jun 8, 2012 | EF1 | 98 km | 7.8 mi | 0 |
| Jun 5, 2005 | EF1 | 48 km | 0.3 mi | 0 |
| Jul 14, 1995 | EF1 | 90 km | 3.5 mi | 0 |
| Apr 26, 1994 | EF1 | 89 km | 4.5 mi | 0 |
| Apr 27, 1984 | EF1 | 80 km | 0.2 mi | 0 |
| Jun 13, 1981 | EF1 | 96 km | 0.1 mi | 0 |
| Jul 12, 1973 | EF1 | 87 km | 19.5 mi | 0 |
| Aug 9, 1958 | EF1 | 98 km | 0.1 mi | 0 |
| Jun 30, 1953 | EF1 | 28 km | 10.9 mi | 0 |
| Aug 19, 2011 | EF0 | 1 km | 1.5 mi | 0 |
| Apr 30, 2010 | EF0 | 98 km | 0.4 mi | 0 |
| Aug 3, 1988 | EF0 | 84 km | 0.2 mi | 0 |
| May 12, 1988 | EF0 | 45 km | 0.2 mi | 0 |
| Jul 11, 1987 | EF0 | 86 km | 6.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
2 wildfires (100+ acres) recorded within 100 km. Largest: BARAGA BUMP (1,047 acres, 2007).
| Year | Name | Acres Burned | Distance |
| 2007 | BARAGA BUMP | 1,047 | 63 km |
| 2009 | PINERY | 695 | 71 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 17°F (-8°C) | 2.2 in | Coldest |
| February | 18°F (-8°C) | 1.4 in | Driest |
| March | 27°F (-3°C) | 1.8 in | |
| April | 39°F (4°C) | 2.0 in | |
| May | 50°F (10°C) | 3.1 in | |
| June | 59°F (15°C) | 3.4 in | |
| July | 67°F (20°C) | 3.1 in | Warmest |
| August | 65°F (18°C) | 3.5 in | Wettest |
| September | 57°F (14°C) | 3.5 in | |
| October | 46°F (8°C) | 2.9 in | |
| November | 33°F (1°C) | 2.6 in | |
| December | 22°F (-6°C) | 2.3 in |
Ontonagon has a seasonal temperature swing of 50°F / from 17°F in January to 67°F in July. Total annual precipitation is 31.8 inches, with August being the wettest month (3.5") and February the driest (1.4").