Thunder Bay weather in August
Temperature, rain and sunshine in August: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in August
Excellent
Best time to visit: June – September
What is the weather like in Thunder Bay in August?
In August, Thunder Bay is warm: daytime highs average 22 °C, and nights cool down to about 16 °C. The sun shines for around 8 hours a day. Rain is frequent, with about 10 rainy days and 68 mm in total. All in all, August is an excellent month for a holiday in Thunder Bay.
August compared
How the weather changes from July to September. Tap a month to open it.
| JulyJul | AugustAug | SeptemberSep | |
|---|---|---|---|
| Score | 86 | 83 | 75 |
| Day | 22° | 22° | 18° |
| Night | 16° | 16° | 13° |
| Sun | 9 h | 8 h | 6 h |
| Rain days | 10 | 10 | 10 |
More details for August
- Daylight
- 14 h 24 min06:50 – 21:14
- UV index
- 7 · highclear sky, noon (estimate)All months
- Muggy days
- 3 daysdew point 18 °C or moreAll months
- Wind
- 21 km/haverage daily peakAll months
- Cloud cover
- 53 %on averageAll months
- Hot days
- 0 days30 °C or more
- Snow days
- 0 days1 cm or more of fresh snowAll months
- Time zone
- UTC−4America/Toronto
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %80 %
- Few rainy daysweight 30 %58 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in August
- Sunscreen
- Sunglasses & sun hat
- Rain jacket or umbrella
Thunder Bay in August: quick answers
Is Thunder Bay hot in August?
Warm rather than hot: in August, daytime highs in Thunder Bay average 22 °C and nights cool to about 16 °C.
Does it rain much in Thunder Bay in August?
Rain is frequent, with about 10 rainy days and 68 mm in total.
Thunder Bay month by month
The whole year in Thunder BayAll destinations: CanadaWhere to go in August
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences