Weather in Thunder Bay in September
Thunder Bay, Canada averages a high of 18.2°C (64.8°F) and low of 11.8°C (53.2°F) in September, with 10 rain days and 9.2 hours of daily sunshine. Travel score: 73.1/100 (Good). The best time to visit Thunder Bay is August.
High
18°C65°F
Low
12°C53°F
🌧️
10
rain days
☀️
9.2
hrs/day sunshine
💧
76%
humidity
73— Good
September in Thunder Bay is mild and occasionally wet — good for most activities.
What are the average temperatures in Thunder Bay?
How much does it rain in Thunder Bay in September?
Thunder Bay receives an average of 80.2mm of rainfall across 10 rainy days in September. The annual total is 654.6mm.
What should I pack for Thunder Bay in September?
Essentials
👟
Comfortable walking shoes
Essential for exploring the city
🧥
Mix of light and warm layers
Mild temperatures around 18°C
Recommended
🧥
Light rain jacket
Some rainy days expected (10 days)
☔
Umbrella
Be prepared for occasional showers
🧴
Sunscreen
Sun protection is still recommended
🕶️
Sunglasses
Useful for sunny periods
Traveling to Canada in September?
Don't let a public holiday surprise you — restaurants, shops, and attractions may be closed.
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Data based on 1994–2024 averages · Last updated: 2024-12-31