Weather in September 2025

Thunder Bay weather in September 2025

The temperatures in Thunder Bay in September are quite cold with temperatures between 9°C and 16°C, warm clothes are a must.

You can expect about 3 to 8 days of rain in Thunder Bay during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.

Our weather forecast can give you a great sense of what weather to expect in Thunder Bay in September 2025.

If you’re planning to visit Thunder Bay in the near future, we highly recommend that you review the 14 day weather forecast for Thunder Bay before you arrive.

Temperatures
Temperatures
16° / 9°
Rainy Days
Rainy Days
5
Snowy Days
Snowy Days
0
Dry Days
Dry Days
25
Rainfall
Rainfall
84
mm
9.8
Sun Hours
9.8
Hrs

Thunder Bay annual weather

Month Temperatures Rainy Days Dry Days Snowy Days Rainfall Weather More details
January -10° / -16° 5 4 23 51 mm
Awful
February -9° / -16° 4 5 20 51 mm
Awful
March -2° / -8° 9 5 19 75 mm
Awful
April 4° / -2° 7 12 12 100 mm
Awful
May 12° / 4° 7 23 2 96 mm
Awful
June 17° / 9° 6 24 0 98 mm
Good
July 21° / 13° 5 26 0 90 mm
Good
August 21° / 13° 4 27 0 87 mm
Good
September 16° / 9° 5 25 0 84 mm
Good
October 8° / 3° 6 20 5 74 mm
Bad
November 1° / -4° 6 10 14 78 mm
Awful
December -6° / -11° 5 6 21 69 mm
Awful
Temperatures in Thunder Bay in September
Rain in Thunder Bay in September

Recommended Hotels in Thunder Bay

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That’s why we run our special tools and found the best hotels in Thunder Bay. Click on hotel for more details.

Weather in Thunder Bay in September - FAQ

What is the average temperature in Thunder Bay in September?
The average temperature in Thunder Bay in September is 9/16° C.
What is the chance of rain in Thunder Bay in September?
On average, there are 5 rainy days in Thunder Bay during September.
Weather wise, is September a good time to visit Thunder Bay?
The weather in Thunder Bay in September is good.
Can it snow in Thunder Bay in September?
On average, there are 0 snowy days in Thunder Bay in September.
More about the weather in Thunder Bay