December in Halton Hills averages a daily high of 2.3°C with nights around -5.6°C. Expect roughly 11.6 wet days totalling 57.3mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Halton Hills is May–September.
Based on GEORGETOWN WWTP, ON CA (4km), 1995–2024. 21 years of December data.