Last updated: June 18, 2025
In Thunder Bay, Canada, the average temperature in August hovers around 17°C (63°F), presenting a pleasant climate ideal for exploration. Expect a minimum of 6°C (44°F) and a maximum of 29°C (84°F), offering a range of comfort for all preferences. With an average precipitation of 77 mm (3.0 in) spread over 9 days, be prepared for occasional showers, and don't forget to embrace the average humidity of 72% that adds to the region's unique charm.
In August in Thunder Bay, the average temperature is 17°C (63°F). The maximum can reach 29°C (84°F) and the minimum can be as low as 6°C (44°F). This makes Thunder Bay an ideal destination for travelers looking for mild weather, perfect for outdoor activities and sightseeing.
In Thunder Bay in August, the precipitation amount is 77 mm (3.0 in) over the course of 9 days.
In Thunder Bay in August, humidity is 72%. With an average temperature of 17°C (63°F), this humidity feels like a muggy embrace, making outdoor activities a bit sticky and requiring plenty of hydration for a comfortable travel experience.
In Thunder Bay in August, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Thunder Bay.
UV Risk Categories
Weather in Thunder Bay varies notably across the year, with each month offering distinct climate conditions. This page compares August’s weather to other months in Thunder Bay, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -13°C (9°F) | 30 mm (1.2 inches) | 95% | low |
| February Weather | -13°C (9°F) | 35 mm (1.4 inches) | 94% | moderate |
| March Weather | -5°C (23°F) | 31 mm (1.2 inches) | 92% | moderate |
| April Weather | 1°C (33°F) | 58 mm (2.3 inches) | 90% | high |
| May Weather | 8°C (47°F) | 52 mm (2.0 inches) | 78% | very high |
| June Weather | 14°C (58°F) | 58 mm (2.3 inches) | 71% | very high |
| July Weather | 19°C (66°F) | 82 mm (3.2 inches) | 70% | very high |
| August Weather | 17°C (63°F) | 77 mm (3.0 inches) | 72% | very high |
| September Weather | 13°C (55°F) | 98 mm (3.9 inches) | 76% | high |
| October Weather | 6°C (43°F) | 87 mm (3.4 inches) | 82% | moderate |
| November Weather | -3°C (27°F) | 51 mm (2.0 inches) | 87% | low |
| December Weather | -9°C (16°F) | 55 mm (2.2 inches) | 94% | low |