Thunder Bay in September
7.0out of 10
Possible, with caveats
Mild: highs around 17°C. Frequent rain: about 10 rainy days.
17°CAvg high
9°CAvg low
10Rainy days (84 mm)
12:20 hDaylight
07:41Sunrise · 20:01 Sunset
Why this score
- Mild: highs around 17°C
- Frequent rain: about 10 rainy days
What to wear and pack
- Layers you can add or remove
- Rain jacket or compact umbrella
How reliable is the forecast?
Rainfall in September is fairly consistent from year to year (2.5 days). Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | -9°C | -18°C | 29 mm | 6 | – | – | 4.2 |
| February | -7°C | -16°C | 22 mm | 5 | – | – | 4.4 |
| March | 0°C | -10°C | 31 mm | 7 | – | – | 4.2 |
| April | 6°C | -3°C | 54 mm | 8 | – | – | 5.1 |
| May | 14°C | 4°C | 66 mm | 10 | – | – | 6.4 |
| June | 19°C | 10°C | 65 mm | 10 | – | – | 7.3 |
| July | 23°C | 14°C | 76 mm | 11 | – | – | 7.7 |
| August | 22°C | 14°C | 67 mm | 9 | – | – | 7.9 |
| September | 17°C | 9°C | 84 mm | 10 | – | – | 7.0 |
| October | 9°C | 3°C | 73 mm | 11 | – | – | 5.6 |
| November | 2°C | -4°C | 49 mm | 8 | – | – | 4.3 |
| December | -5°C | -13°C | 38 mm | 8 | – | – | 4.1 |
Frequently asked questions
How hot is Thunder Bay in September?
Daytime highs average 17°C and nights about 9°C.
When is the best time to visit Thunder Bay?
The best months are August, July.