May in Graz averages a daily high of 21.5°C with nights around 10.3°C. Expect roughly 13.1 wet days totalling 95.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Graz is April–September.
Based on GRAZ, AU (1.9km), 1995–2024. 28 years of May data.