December in Brest averages a daily high of -0.2°C with nights around -4.9°C. Expect roughly 12.6 wet days totalling 33.2mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Brest is May–September.
Based on BREST, BO (2.5km), 1995–2024. 11 years of December data.