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 2010-03-10 11:00:00

	2°C Fog
		Feels Like		Wind	0 km/h
		Humidity	100 %	Pressure	101.0 kPa rising
		Dew Point	2.2°C	Visibility	9.7 km
		Air Quality		Temperature	2.2°C

Short Term Forecast

	Wednesday	Wednesday Night	Thursday	Friday	Saturday
	A Mix Of Sun And Cloud	A Few Showers	Chance Of Showers	Chance Of Showers	A Mix Of Sun And Cloud
Low		3°C		5°C	3°C
High	8°C		6°C	9°C	12°C

Detailed Thunder Bay Weather Forecast

Wednesday	A mix of sun and cloud. High 8. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Wednesday Night	Cloudy. A few showers beginning near midnight. Low plus 3. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Thursday	Cloudy with 60 percent chance of showers. High 6. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Friday	Cloudy with 60 percent chance of showers. Low plus 5. High 9. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Saturday	A mix of sun and cloud. Low plus 3. High 12. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Sunday	Sunny. Low plus 3. High 12. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Monday	Sunny. Low minus 2. High 8. Forecast issued 11:30 AM EDT Wednesday 10 March 2010
Tuesday	Sunny. Low minus 4. High 7. Forecast issued 11:30 AM EDT Wednesday 10 March 2010