December in Rennes averages a daily high of 9.7°C with nights around 3.6°C. Expect roughly 15.3 wet days totalling 73.1mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Rennes is May–September.
Based on RENNES ST JACQUES, FR (6.4km), 1995–2024. 30 years of December data.