Cantabria is famously green — it rains often and the Atlantic keeps temperatures mild year-round. Summers (July–August) are warm but rarely hot, with temperatures in the low 20s Celsius; this is the peak beach season and when the city is most animated. Spring and autumn are quieter, good for walking, and the light is beautiful. Winters are mild by northern European standards but can be grey and wet.
The International Festival of Santander, held every August since 1952, brings classical music, dance, and theatre to the city — worth timing a visit around if you enjoy live performance. The Semana Grande festival in late July is the local feria, with street parties, concerts, and fireworks over the bay.