December in Altona averages a daily high of 5.3°C with nights around 0.9°C. Expect roughly 16.3 wet days totalling 69mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Altona is May–September.
Based on HAMBURG NEUWIEDENTHAL, GM (8.2km), 1995–2024. 30 years of December data.