December in Ljubljana averages a daily high of 4.4°C with nights around -0.7°C. Expect roughly 11.1 wet days totalling 111.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Ljubljana is May–September.
Based on LJUBLJANA BEZIGRAD, SI (1.9km), 1995–2024. 29 years of December data.