In December, Thunder Bay typically sees daytime highs of -6.6°C and overnight lows around -16.3°C. Compared to the annual average high of 8.0°C, December runs -14.6°C.
December in Thunder Bay averages a daytime high of -6.6°C and an overnight low of -16.3°C.
December runs -14.6°C compared to Thunder Bay's annual average high of 8.0°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near -6.6°C and cooler evenings around -16.3°C.