Thunder Bay
August
Weather in Thunder Bay for August 2025
Your guide to Thunder Bay weather in August - trends and predictions
In general, the average temperature in Thunder Bay at the beginning of August is 23.1 °C. As the month progressed, temperatures tended to moderately fall, reaching an average of 21.7 °C by the end of August.
The climate of Thunder Bay in August is notably wet, with an average of 15 rainy days.
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16
Dry days
15
Rainy days
0
Snow days
21°/12°
Temperatures
16 km/h
Avg max wind
75 %
Avg humidity
Thunder Bay in August average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  23° | 2 28° | 3  25° | ||||
| 4 21° | 5 21° | 6 21° | 7  23° | 8  22° | 9 17° | 10 17° |
| 11 18° | 12 19° | 13 22° | 14  22° | 15 21° | 16 20° | 17 22° |
| 18 23° | 19 22° | 20 21° | 21 21° | 22 20° | 23 21° | 24 23° |
| 25 21° | 26 24° | 27  21° | 28 18° | 29  19° | 30 25° | 31 24° |
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Temperatures trend during August in Thunder Bay
See the weather trend as well as the moving average line
August weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Aug. | Overcast | 23° /14° | 0.1 mm | 6 | |
| 2 Aug. | Overcast | 28° /15° | 1.2 mm | 7 | |
| 3 Aug. | Partly cloudy | 25° /16° | 0.1 mm | 7 | |
| 4 Aug. | Partly cloudy | 21° /13° | 0 mm | 6 | |
| 5 Aug. | Overcast | 21° /11° | 0 mm | 6 | |
| 6 Aug. | Overcast | 21° /12° | 0.1 mm | 6 | |
| 7 Aug. | Patchy rain possible | 23° /14° | 0.2 mm | 6 | |
| 8 Aug. | Moderate rain at times | 22° /13° | 5.3 mm | 5 | |
| 9 Aug. | Overcast | 17° /11° | 1.1 mm | 4 | |
| 10 Aug. | Patchy rain possible | 17° /10° | 0.8 mm | 4 | |
| 11 Aug. | Moderate or heavy rain shower | 18° /11° | 13.7 mm | 5 | |
| 12 Aug. | Overcast | 19° /12° | 0.9 mm | 5 | |
| 13 Aug. | Overcast | 22° /13° | 0 mm | 5 | |
| 14 Aug. | Sunny | 22° /13° | 0 mm | 6 | |
| 15 Aug. | Partly cloudy | 21° /13° | 13.8 mm | 5 | |
| 16 Aug. | Patchy rain possible | 20° /14° | 12.9 mm | 5 | |
| 17 Aug. | Patchy rain possible | 22° /14° | 0.7 mm | 5 | |
| 18 Aug. | Sunny | 23° /12° | 0 mm | 6 | |
| 19 Aug. | Patchy rain possible | 22° /13° | 0.1 mm | 6 | |
| 20 Aug. | Partly cloudy | 21° /13° | 0 mm | 6 | |
| 21 Aug. | Moderate rain at times | 21° /11° | 0.9 mm | 6 | |
| 22 Aug. | Moderate rain at times | 20° /12° | 10.6 mm | 5 | |
| 23 Aug. | Patchy rain possible | 21° /13° | 4.1 mm | 5 | |
| 24 Aug. | Patchy rain possible | 23° /14° | 1.4 mm | 5 | |
| 25 Aug. | Light rain shower | 21° /13° | 10.5 mm | 5 | |
| 26 Aug. | Overcast | 24° /13° | 4.8 mm | 6 | |
| 27 Aug. | Mist | 21° /8° | 14 mm | 5 | |
| 28 Aug. | Light rain shower | 18° /11° | 0.9 mm | 5 | |
| 29 Aug. | Patchy light rain | 19° /10° | 1.5 mm | 5 | |
| 30 Aug. | Mist | 25° /11° | 0.9 mm | 6 | |
| 31 Aug. | Overcast | 24° /12° | 0.9 mm | 5 | |
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Important Notice
Our weather forecast for Thunder Bay in August is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Thunder Bay forecast closer to your planned date for the most up-to-date weather information.
Thunder Bay in August - FAQ
What are the expected maximum and minimum temperatures in Thunder Bay during August?
Enjoy moderate daytime temperatures of up to 21° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Thunder Bay during August?
Significant rainfall exceeding 114.8 mm is expected in Thunder Bay during August, occurring over more than 15 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Thunder Bay during August?
The average wind speed in Thunder Bay during August is 16 km/h, suggesting breezy to windy conditions, depending on your activities.
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