Measurements:
°C
°F
Thunder Bay
60°F
NW 5 mph
Feels like: 60°F
Precip: 7%
World Resorts Canada Thunder Bay Weather

Thunder Bay Sea Water Temperature

Current Sea Water Temperature:
+57.8°F
Maximum Sea Water Temperature in September: 67.6°F
Minimum Sea Water Temperature in September: 50.8°F
Average water temperature in September: 61.3°F

Sea Water Temperature for the Last 10 Days:

September 28 57.8°F September 23 56.8°F
September 27 56.6°F September 22 57.4°F
September 26 56.2°F September 21 57.2°F
September 25 56.2°F September 20 57.8°F
September 24 56.0°F September 19 56.4°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: 2026 2025 2024

The average sea surface temperature in August 2026 for Thunder Bay was 62.5°F. The maximum and minimum values were 57.0°F and 65.2°F respectively.

Sea Water Temperature in September

Select Year: 2026 2025 2024

The average sea surface temperature in September 2026 for Thunder Bay was 60.9°F. The maximum and minimum values were 50.8°F and 67.2°F respectively.

Sea Water Temperature in July

Select Year: 2026 2025 2024

The average sea surface temperature in July 2026 for Thunder Bay was 52.0°F. The maximum and minimum values were 44.2°F and 61.2°F respectively.

Best Time to Visit Thunder Bay
The most sunny months:
July 14 days
August 14 days
September 13 days
The most warm months:
July 73.4 °F
August 71.9 °F
June 65.3 °F
Warmest sea temperature:
August 64.6 °F
September 61.3 °F
July 59.4 °F
The most cold months:
January 9.8 °F
February 11.1 °F
December 17.9 °F
The most rainy months:
September 2 days
April 2 days
August 2 days
The most windy months:
November 9 mph
December 9 mph
April 8 mph

Thunder Bay on the Weather Map

Canada Resorts:
NAME
F°
Halifax +56
Moncton +54
Montreal +52
Nanaimo +58
Niagara Falls +64
Ottawa +54
Prince Edward Island +56
Quebec +50
Saint Andrews +56
St. John's +42
Sydney +54
Toronto +72
Vancouver +58
Victoria +58
Winnipeg +52
24 Hours Weather Forecast
Thunder Bay
Local time: 17:57
28 sep, monday
1800 60°F
NW
5 mph
2100 58°F
W
2 mph
29 sep, tuesday
0000 58°F
NW
4 mph
0300 58°F
NW
4 mph
0600 58°F
N
5 mph
0900 58°F
N
9 mph
1200 60°F
N
12 mph
1500 62°F
NE
12 mph