May in Luxembourg averages a daily high of 18.4°C with nights around 8.8°C. Expect roughly 12.7 wet days totalling 74.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Luxembourg is May–September.
Based on LUXEMBOURG AIRPORT, LU (5.4km), 1995–2024. 30 years of May data.