Weather in Thunder Bay District for September 2025
Until now, September 2025 in Thunder Bay District is cooler than usual, with temperatures averaging 15.4 °C, this is -3.9 °C below the typical seasonal average.
Expect cooler weather in the next days in Thunder Bay District with the forecast suggesting a temperature of 17.7 °C, lower than the historical average.
In general, the average temperature in Thunder Bay District at the beginning of September is 20.3 °C. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 17.4 °C by the end of September.
Thunder Bay District experiences moderate rainfall in September, with an average of 9 rainy days and a total precipitation of 58.2 mm.
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Thunder Bay District Weather September
Temperatures trend during September in Thunder Bay District
September weather in Thunder Bay District day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Patchy rain possible | 21° /11° | 0 mm | 5 | |
| 2 Sept. |  Sunny | 25° /12° | 4.2 mm | 6 | |
| 3 Sept. |  Partly cloudy | 23° /10° | 16.9 mm | 5 | |
| 4 Sept. | Partly cloudy | 20° /11° | 1.4 mm | 5 | |
| 5 Sept. |  Fog | 19° /10° | 4.2 mm | 4 | |
| 6 Sept. | Light rain shower | 16° /6° | 11 mm | 4 | |
| 7 Sept. | Partly cloudy | 18° /6° | 0 mm | 5 | |
| 8 Sept. | Mist | 19° /6° | 3.6 mm | 4 | |
| 9 Sept. |  Light drizzle | 18° /10° | 10 mm | 5 | |
| 10 Sept. | Light rain shower | 19° /11° | 1 mm | 5 | |
| 11 Sept. |  Overcast | 18° /10° | 0 mm | 4 | |
| 12 Sept. | Overcast | 16° /9° | 0 mm | 4 | |
| 13 Sept. | Sunny | 20° /10° | 0 mm | 5 | |
| 14 Sept. | Mist | 18° /10° | 0 mm | 4 | |
| 15 Sept. | Mist | 20° /12° | 0.6 mm | 5 | |
| 16 Sept. | Fog | 23° /14° | 0 mm | 1.1 | |
| 17 Sept. |  Heavy rain | 25° /14° | 61.4 mm | 1.1 | |
| 18 Sept. | Partly cloudy | 15° /10° | 0 mm | 0.9 | |
| 19 Sept. | Partly cloudy | 15° /11° | 0 mm | 1.2 | |
| 20 Sept. | Patchy rain possible | 14° /11° | 1.4 mm | 0 | |
| 21 Sept. | Fog | 17° /13° | 0.1 mm | 3 | |
| 22 Sept. | Patchy rain possible | 17° /13° | 1.8 mm | 3 | |
| 23 Sept. | Sunny | 20° /9° | 0 mm | 5 | |
| 24 Sept. | Sunny | 20° /14° | 0 mm | 5 | |
| 25 Sept. | Sunny | 13° /7° | 0 mm | 4 | |
| 26 Sept. | Sunny | 17° /4° | 0 mm | 3 | |
| 27 Sept. | Sunny | 18° /9° | 0 mm | 4 | |
| 28 Sept. | Sunny | 18° /10° | 0 mm | 4 | |
| 29 Sept. | Partly cloudy | 16° /12° | 0 mm | 4 | |
| 30 Sept. | Light rain shower | 20° /9° | 1.7 mm | 5 | |
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Thunder Bay District in September - FAQ
September rainfall patterns in Thunder Bay District
UV exposure in Thunder Bay District during September
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Where is Thunder Bay District?Get accurate weather forecasts for Thunder Bay District, located at latitude 48.382 and longitude -89.25. Stay updated with localized weather information tailored for Thunder Bay District.