December in Winterthur averages a daily high of 4.1°C with nights around -0.3°C. Expect roughly 14.3 wet days totalling 84.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Winterthur is May–September.
Based on ZUERICH FLUNTERN, SZ (18.1km), 1995–2024. 30 years of December data.