December in Bolu averages a daily high of 8.2°C with nights around -0.5°C. Expect roughly 13.6 wet days totalling 51.4mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Bolu is June–October.
Based on BOLU, TU (0.6km), 1995–2024. 27 years of December data.