December in Bilbao averages a daily high of 14.3°C with nights around 6.2°C. Expect roughly 15.1 wet days totalling 131.4mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Bilbao is May–October.
Based on BILBAO AEROPUERTO, SP (4.2km), 1995–2024. 29 years of December data.