December in Mustamäe averages a daily high of 0.9°C with nights around -3.4°C. Expect roughly 19.1 wet days totalling 59.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Mustamäe is June–August.
Based on TALLINN, EN (4.5km), 1995–2024. 30 years of December data.