December in Vilnius averages a daily high of -0.4°C with nights around -4.6°C. Expect roughly 18.5 wet days totalling 46mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Vilnius is June–September.
Based on VILNIUS, LH (13.1km), 1995–2024. 14 years of December data.