December in Graz averages a daily high of 4.2°C with nights around -1.8°C. Expect roughly 7.3 wet days totalling 38.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Graz is April–September.
Based on GRAZ, AU (1.9km), 1995–2024. 28 years of December data.