September in Altona averages a daily high of 19.6°C with nights around 10.8°C. Expect roughly 12.6 wet days totalling 58.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Altona is May–September.
Based on HAMBURG NEUWIEDENTHAL, GM (8.2km), 1995–2024. 30 years of September data.