May in Trondheim averages a daily high of 13.7°C with nights around 5.3°C. Expect roughly 16 wet days totalling 46mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Trondheim is June–August.
Based on TRONDHEIM VOLL, NO (3.6km), 1995–2024. 26 years of May data.