May in Bern averages a daily high of 19.2°C with nights around 8.1°C. Expect roughly 13.8 wet days totalling 85.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Bern is June–September.
Based on PAYERNE, SZ (40.5km), 1995–2024. 30 years of May data.