The most humid part of Spain is the Northern Atlantic Coast, encompassing regions such as Galicia, Asturias, Cantabria, and the Basque Country. This area, often called "Green Spain," has a maritime climate heavily influenced by the Atlantic Ocean, resulting in average relative humidity levels consistently between 70% and 90%. Unlike the dry, sun-baked plains of central Spain (Madrid) or the hot, Mediterranean south, the north experiences frequent mist, drizzle, and high-fidelity lushness that makes it resemble Ireland or the Pacific Northwest. Specifically, cities like San Sebastián and Vigo are known for their damp air and high rainfall totals. On the Mediterranean side, cities like Barcelona can also feel very humid during the summer months due to the warm sea air, but they do not match the year-round persistent moisture of the Atlantic north. For travelers in 2026, this humidity is what keeps the northern landscapes strikingly verdant, though it also means a good raincoat is an essential piece of travel gear regardless of the season.