December in Mikkeli averages a daily high of -2.6°C with nights around -8.1°C. Expect roughly 18.2 wet days totalling 55.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Mikkeli is June–August.
Based on MIKKELI LENTOASEMA, FI (3.3km), 1995–2024. 28 years of December data.