All Countries
Weather & Climate in Thunder Bay, ON
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Thunder Bay has a cool climate with an average annual temperature of 39°F (4°C). Winters average 11°F in January while summers reach 63°F in July. The area gets 285 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 31.5 inches. The area receives 81.3 inches of snow annually, making winter weather a significant factor for residents. The city sits at an elevation of 617 feet.
Temperature
11°F Jan (-12°C)
63°F Jul (17°C)
| Annual Average | 39.3°F |
| 27% below US avg | |
| January Average | 11°F (-12°C) |
| July Average | 63°F (17°C) |
| Sunny Days | 285 days/yr |
Geography
| Elevation | 617 ft (188 m) |
| Area | 126.6 sq mi (327.8 km²) |
| Population Density | 860/sq mi |
| Coordinates | 48.3820°N, 89.2502°W |
| Timezone | America/Toronto |
Precipitation & Snow
Air Quality
Earthquake History
1 earthquake (M2.5+) recorded within 150 km since 1990. Strongest on record: M2.7.
| Mar 19, 2018 | 75 km ESE of Atikokan, Canada | M2.7 | 105 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Wildfire History
1 wildfire (100+ acres) recorded within 100 km. Largest: TUESDAY (533 acres, 2002).
| Year | Name | Acres Burned | Distance |
| 2002 | TUESDAY | 533 | 79 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 11°F (-12°C) | 1.4 in | |
| February | 10°F (-12°C) | 1.0 in | Coldest, Driest |
| March | 22°F (-6°C) | 1.6 in | |
| April | 36°F (2°C) | 1.7 in | |
| May | 49°F (10°C) | 2.7 in | |
| June | 59°F (15°C) | 3.2 in | |
| July | 63°F (17°C) | 3.5 in | Wettest |
| August | 63°F (17°C) | 3.3 in | Warmest |
| September | 54°F (12°C) | 3.2 in | |
| October | 43°F (6°C) | 2.6 in | |
| November | 28°F (-2°C) | 2.2 in | |
| December | 13°F (-10°C) | 1.6 in |
Thunder Bay has a seasonal temperature swing of 53°F / from 10°F in February to 63°F in August. Total annual precipitation is 28.1 inches, with July being the wettest month (3.5") and February the driest (1.0").