In December, St. Catharines typically sees daytime highs of 1.9°C and overnight lows around -4.6°C. Compared to the annual average high of 12.9°C, December runs -11.0°C.
December in St. Catharines averages a daytime high of 1.9°C and an overnight low of -4.6°C.
December runs -11.0°C compared to St. Catharines's annual average high of 12.9°C, ranking #10 of 12 months by warmth.
Plan for daytime highs near 1.9°C and cooler evenings around -4.6°C.