The climate of Thunder Bay is influenced by Lake Superior, resulting in cooler summer temperatures and warmer winter temperatures. So when visiting, it’s important to pack for cooler weather and plan to wear layers that can easily accodate the temperature for that part of the day.

The average daily temperatures range from a high of 62 F/17.6 °C in July and a low of 5°F/-14.8 °C in January; the average daily high in July is 75°F/24.2 °C and the average daily high in January is 17°F/-8.6 °C. Summer daytime temperatures vary from 15° C to 30° C, while nights tend to be cooler and less humid than southern locations.

The summer period is well suited to both active and passive outdoor recreational pursuits. Recent winter daytime temperatures have ranged from springlike to relatively cold with sunny days. This type of climate is well suited to all kinds of active outdoor recreational pursuits. Spring and autumn are short with cool days and evenings.

Winter outdoor recreation often extends well into April while summer culminates in a spectacular show of colours in the fall.Precipitation is highly variable from year to year. The annual average rainfall is 527.3 mm while the average snowfall is 213 cm.
On average, Thunder Bay is the sunniest location in eastern, sunnier than any city in Canada located to the east of it.

Current Thunder Bay Weather

Observed at Thunder Bay Airport on 2010-02-08 17:00:00

	-8°C Partly Cloudy
		Feels Like	-11	Wind	E 5 km/h
		Humidity	63 %	Pressure	102.9 kPa falling
		Dew Point	-14.0°C	Visibility	32.2 km
		Air Quality		Temperature	-8.3°C

Short Term Forecast

	Monday Night	Tuesday	Tuesday Night	Wednesday	Thursday
	Cloudy Periods	Sunny	A Few Clouds	A Mix Of Sun And Cloud	A Mix Of Sun And Cloud
Low	-18°C		-15°C		-16°C
High		-8°C		-7°C	-7°C

Detailed Thunder Bay Weather Forecast

Monday Night	Cloudy periods. Low minus 18. Forecast issued 4:00 PM EST Monday 08 February 2010
Tuesday	Sunny. High minus 8. Forecast issued 4:00 PM EST Monday 08 February 2010
Tuesday Night	Clear. Increasing cloudiness after midnight. Low minus 15. Forecast issued 4:00 PM EST Monday 08 February 2010
Wednesday	A mix of sun and cloud. High minus 7. Forecast issued 4:00 PM EST Monday 08 February 2010
Thursday	A mix of sun and cloud. Low minus 16. High minus 7. Forecast issued 4:00 PM EST Monday 08 February 2010
Friday	A mix of sun and cloud. Low minus 16. High minus 7. Forecast issued 4:00 PM EST Monday 08 February 2010
Saturday	A mix of sun and cloud. Low minus 16. High minus 6. Forecast issued 4:00 PM EST Monday 08 February 2010
Sunday	A mix of sun and cloud. Low minus 15. High minus 5. Forecast issued 4:00 PM EST Monday 08 February 2010