Measurements:
°C
°F
CURRENT WEATHER
18:06
Thunder Bay
74°F
N 14 mph
Feels like: 80°F
Precip: 87%
World Resorts Canada Thunder Bay Weather

7 Day Weather Forecast

09.08
tue
DAY
66°F
N 16 mph
precip
91%
NIGHT
68°F
NE 11 mph
precip
83%
09.09
wed
DAY
66°F
E 16 mph
precip
11%
NIGHT
54°F
SE 7 mph
precip
9%
09.10
thu
DAY
58°F
SE 5 mph
precip
2%
NIGHT
56°F
N 6 mph
precip
12%
09.11
fri
DAY
68°F
NE 16 mph
precip
24%
NIGHT
64°F
N 22 mph
precip
66%
09.12
sat
DAY
58°F
E 11 mph
precip
10%
NIGHT
56°F
E 9 mph
precip
15%
09.13
sun
DAY
56°F
SE 11 mph
precip
3%
NIGHT
54°F
SE 5 mph
precip
4%
09.14
mon
DAY
54°F
W 8 mph
precip
18%
NIGHT
54°F
NW 16 mph
precip
82%

Thunder Bay Sea Water Temperature in September, °F

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Thunder Bay was 15.5°F. The maximum and minimum values were 14.1°F and 16.8°F respectively.

Thunder Bay on the Weather Map

Best Time to Visit Thunder Bay
The most sunny months:
July 14 days
September 14 days
August 14 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
August 2 days
April 2 days
The most windy months:
November 9 mph
December 9 mph
April 8 mph
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