September in Ulm averages a daily high of 17.9°C with nights around 7.4°C. Expect roughly 11.8 wet days totalling 63.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Ulm is June–September.
Based on MERKLINGEN, GM (21km), 1995–2024. 30 years of September data.