June in Thornhill averages a daily high of 24.8°C with nights around 13.4°C. Expect roughly 11.4 wet days totalling 100.1mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Thornhill is May–September.
Based on TORONTO NORTH YORK, ON CA (4.9km), 1995–2024. 26 years of June data.