Measurements:
°C
°F
Thunder Bay
56°F
N 3 mph
Feels like: 56°F
Precip: 8%
World Resorts Canada Thunder Bay Weather

Thunder Bay Sea Water Temperature

Current Sea Water Temperature:
+48.4°F
Maximum Sea Water Temperature in June: 65.2°F
Minimum Sea Water Temperature in June: 36.0°F
Average water temperature in June: 47.2°F

Sea Water Temperature for the Last 10 Days:

June 17 48.4°F June 12 43.8°F
June 16 43.4°F June 11 43.6°F
June 15 45.0°F June 10 43.0°F
June 14 45.0°F June 09 42.4°F
June 13 43.8°F June 08 40.8°F

When is the Warmest Sea for Thunder Bay?

According to our data for the last three years for Thunder Bay the highest average sea water temperature was in August, September and July.

Average Water Temperature by Month, °F

Sea Water Temperature in August

Select Year: 2025 2024 2023

The average sea surface temperature in August 2025 for Thunder Bay was 64.6°F. The maximum and minimum values were 61.0°F and 70.0°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Thunder Bay was 61.0°F. The maximum and minimum values were 58.2°F and 63.6°F respectively.

Sea Water Temperature in July

Select Year: 2025 2024 2023

The average sea surface temperature in July 2025 for Thunder Bay was 62.4°F. The maximum and minimum values were 55.8°F and 66.6°F respectively.

Best Time to Visit Thunder Bay
The most sunny months:
September 14 days
August 14 days
July 12 days
The most warm months:
July 71.5 °F
August 71.2 °F
June 64.4 °F
Warmest sea temperature:
August 64.9 °F
September 61.3 °F
July 60.6 °F
The most cold months:
January 9.8 °F
February 11.1 °F
December 17.9 °F
The most rainy months:
September 2 days
August 2 days
April 2 days
The most windy months:
November 9 mph
December 9 mph
April 8 mph

Thunder Bay on the Weather Map

Canada Resorts:
NAME
Halifax +66
Kingston +62
Montreal +68
Ottawa +64
Prince Edward Island +56
Quebec +66
Saint John +60
Sydney +60
Thunder Bay +56
Tofino +56
Toronto +64
Vancouver +58
Victoria +54
Winnipeg +64
Yellowknife +54
24 Hours Weather Forecast
Thunder Bay
Local time: 08:57
17 jun, wednesday
0900 56°F
N
3 mph
1200 66°F
NW
7 mph
1500 70°F
NW
7 mph
1800 62°F
NW
6 mph
2100 50°F
W
2 mph
18 jun, thursday
0000 44°F
SE
3 mph
0300 44°F
SE
4 mph
0600 46°F
SE
7 mph