Measurements:
°C
°F
Thunder Bay
16°F
SE 3 mph
Feels like: 8°F
Precip: 0%
World Resorts Canada Thunder Bay Weather

Thunder Bay Sea Water Temperature

Current Sea Water Temperature:
+30.8°F
Maximum Sea Water Temperature in March: 32.2°F
Minimum Sea Water Temperature in March: 30.4°F
Average water temperature in March: 31.1°F

Sea Water Temperature for the Last 10 Days:

March 29 30.8°F March 24 30.6°F
March 28 30.8°F March 23 30.6°F
March 27 30.8°F March 22 30.6°F
March 26 30.8°F March 21 30.8°F
March 25 30.8°F March 20 30.8°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 9 mph

Thunder Bay on the Weather Map

Canada Resorts:
NAME
Halifax +28
Moncton +28
Montreal +32
Niagara Falls +34
Ottawa +30
Prince Edward Island +26
Quebec +18
Rocky Harbour +10
Saint John +30
St. John's +18
Sydney +26
Toronto +34
Vancouver +36
Victoria +32
Winnipeg +18
24 Hours Weather Forecast
Thunder Bay
Local time: 03:11
30 mar, monday
0600 16°F
SE
6 mph
0900 20°F
S
5 mph
1200 32°F
SW
7 mph
1500 32°F
W
7 mph
1800 32°F
W
7 mph
2100 26°F
SW
6 mph
31 mar, tuesday
0000 24°F
SW
7 mph
0300 24°F
W
11 mph