April in Altona averages a daily high of 14.4°C with nights around 4.7°C. Expect roughly 11.7 wet days totalling 40.6mm. 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 April data.