May in Lethbridge averages a daily high of 18.2°C with nights around 4.8°C. Expect roughly 8.7 wet days totalling 50mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Lethbridge is July–September.
Based on LETHBRIDGE CDA, AB CA (3.7km), 1995–2024. 27 years of May data.