June in Sarnia averages a daily high of 25.1°C with nights around 14.8°C. Expect roughly 10.9 wet days totalling 88.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Sarnia is May–September.
Based on PORT HURON, MI US (1.3km), 1995–2024. 30 years of June data.