April in Bilbao averages a daily high of 18.3°C with nights around 8.3°C. Expect roughly 14 wet days totalling 85.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Bilbao is May–October.
Based on BILBAO AEROPUERTO, SP (4.2km), 1995–2024. 30 years of April data.