September in Luxembourg averages a daily high of 19.3°C with nights around 10.4°C. Expect roughly 10.4 wet days totalling 64.1mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Luxembourg is May–September.
Based on LUXEMBOURG AIRPORT, LU (5.4km), 1995–2024. 30 years of September data.