May in Bonn averages a daily high of 19.2°C with nights around 8.6°C. Expect roughly 12.6 wet days totalling 70.7mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Bonn is May–September.
Based on BONN ROLEBER, GM (6.9km), 1995–2024. 24 years of May data.