May in Newmarket averages a daily high of 20.3°C with nights around 6.2°C. Expect roughly 10.8 wet days totalling 67.2mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Newmarket is May–September.
Based on BALDWIN, ON CA (26.9km), 1995–2024. 19 years of May data.