December in Sant Martí averages a daily high of 14.9°C with nights around 6.5°C. Expect roughly 5.4 wet days totalling 35.6mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Sant Martí is May–July.
Based on BARCELONA AEROPUERTO, SP (17.6km), 1995–2024. 30 years of December data.