Weatheo

Thunder Bay Weather by Month

Average temperatures, rainfall and humidity for Thunder Bay, Canada, month by month, built from OpenWeather’s historical records. Use it to see what a typical Thunder Bay month looks like before you travel — then check the live Thunder Bay forecast for the days ahead.

Warmest month

July

27°C average high

Coolest month

February

-10°C average low

Wettest month

June

83 mm of rain

Driest month

February

7 mm of rain

Average temperature and rainfall in Thunder Bay by month

Averages of the daily highs and lows recorded in each month, with total rainfall, mean humidity and mean wind speed.

MonthAvg highAvg lowRecord low / highRainfallHumidityWind
January-3°C-10°C-31°C / 16°C
12 mm
77%14 km/h
February-1°C-10°C-29°C / 20°C
7 mm
73%15 km/h
March5°C-4°C-27°C / 22°C
33 mm
72%15 km/h
April12°C2°C-11°C / 29°C
63 mm
69%17 km/h
May20°C9°C-2°C / 33°C
66 mm
66%14 km/h
June25°C15°C3°C / 35°C
83 mm
69%13 km/h
July27°C17°C8°C / 35°C
52 mm
72%11 km/h
August26°C16°C7°C / 33°C
66 mm
77%10 km/h
September23°C13°C2°C / 34°C
62 mm
78%11 km/h
October15°C6°C-18°C / 31°C
67 mm
75%13 km/h
November8°C0°C-16°C / 24°C
39 mm
74%14 km/h
December1°C-6°C-24°C / 19°C
28 mm
79%14 km/h

Best time to visit Thunder Bay

The most comfortable time to visit Thunder Bay is generally June and August to September, balancing mild daytime temperatures against the driest stretch of the year. The city has strongly marked seasons and rain concentrates around June, totalling about 579 mm a year.

Travellers who prefer heat should aim for July, when highs average 27°C. June is the month to avoid if rain would spoil your plans — it averages 83 mm, roughly 11× the rainfall of the driest month (February).

Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the Thunder Bay forecast for what is happening now.

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