April in Castelldefels averages a daily high of 18.7°C with nights around 10.8°C. Expect roughly 6.7 wet days totalling 47.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Castelldefels is May–July.
Based on BARCELONA AEROPUERTO, SP (8.5km), 1995–2024. 29 years of April data.