Weather in Thunder Bay: August
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Average day temperature: | 69.7°F |
| Average night temperature: | 58.6°F | |
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Sea water temperature: | 63.0°F |
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Number of sunny days: | 14 days |
| Day length: | 13.4 - 15.0 hours | |
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Number of rainy days: | 2 days |
| Precipitation totals: | 1.2 in. | |
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forecast
| Thunder Bay |
temperature
| Thunder Bay |
Air temperature in August, °F
The highest day temperature during August of 2026 was 85°F. At the same time the lowest night temperature was 49°F. Daily and nightly averages during August were 73.5°F and 56.3°F.
Sea water temperature in Thunder Bay in August, °F
The average sea water temperature in August of 2026 was 61.2°F. The highest and lowest sea temperatures during the month were 63.7°F and 56.3°F.
Mostly all days in August are sunny but cloudy days are also possible.
Precipitation total in August, in.
Precipitation total value in Thunder Bay in August is 1.2 in. Other months of the year show relatively similar values.
The average wind speed value in August is 6.5 mph It makes August one of the least windy months of the year.
This chart shows average number of hours during the day when sunlight can reach the ground. It depends on day length and cloudiness during the day. The average number of sunny hours in August is: 8.8.
Best time for vacation in Thunder Bay
Thunder Bay on a weather map
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