May in Uppsala averages a daily high of 17°C with nights around 5.7°C. Expect roughly 10.1 wet days totalling 40.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Uppsala is May–September.
Based on UPPSALA AUT, SW (0.5km), 1995–2024. 30 years of May data.