Thunder Bay is a city close to Lake Superior.
August is the month with the highest water temperature at 61.5°F / 16.4°C.
The coldest month is March with an average water temperature of 31.8°F / -0.1°C.
May is the driest at 0.2in / 6.3mm and December the wettest month with 1.7in / 43.9mm.
With an average air temperature of 66°F / 18.9°C, July is the warmest month in a year. January is the coldest with 8.2°F / -13.2°C average air temperature.
The Climate is described as Warm-summer humid continental climate.
Best time to Visit would be in June, July, August, September.