In August, Thunder Bay typically sees daytime highs of 22.2°C and overnight lows around 9.6°C. Compared to the annual average high of 8.0°C, August runs +14.2°C.
August in Thunder Bay averages a daytime high of 22.2°C and an overnight low of 9.6°C.
August runs +14.2°C compared to Thunder Bay's annual average high of 8.0°C, ranking #2 of 12 months by warmth.
Plan for daytime highs near 22.2°C and cooler evenings around 9.6°C.