December in Waterloo averages a daily high of 0.8°C with nights around -5.2°C. Expect roughly 11.8 wet days totalling 68.2mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Waterloo is May–September.
Based on ROSEVILLE, ON CA (13.6km), 1995–2024. 24 years of December data.