December in Boulogne-Billancourt averages a daily high of 8.8°C with nights around 2.6°C. Expect roughly 16 wet days totalling 60.8mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Boulogne-Billancourt is May–September.
Based on PARIS MONTSOURIS, FR (7.2km), 1995–2024. 16 years of December data.