December in Bern averages a daily high of 4.4°C with nights around -1°C. Expect roughly 12.2 wet days totalling 66mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Bern is June–September.
Based on PAYERNE, SZ (40.5km), 1995–2024. 30 years of December data.