December in Biysk averages a daily high of -8.4°C with nights around -18°C. Expect roughly 14.7 wet days totalling 39.9mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Biysk is May–September.
Based on BIJSK ZONALNAJA, RS (23.2km), 1995–2024. 26 years of December data.