Spanish Coast Records Historic Sea Warming in May. At the end of May, water temperatures off the Spanish coast reached all-time highs. Eighteen out of twenty-nine oceanographic buoys recorded new records, and near Menorca, the water warmed to 26.58 °C. Experts warn of risks to marine ecosystems.
26.58 °C — this was the water temperature recorded by the buoy at the port of Maó in Menorca on May 27. This is not just a new record for May: according to Puertos del Estado, the sea has never been this warm at the start of summer in Spain. In total, 18 out of 29 oceanographic buoys across the country—from Galicia and the Bay of Biscay to the Mediterranean—showed historic highs for this month.
The abnormal heatwave that swept Spain and much of Europe at the end of May affected not only land. According to Puertos del Estado, water temperature in the Cantabrian Sea was 1.5–2 degrees above normal, and in the Mediterranean and around the Balearic Islands, readings also surpassed all previous figures. Among the record holders are the buoy near Dragonera Island (26.2 °C), stations in Tarragona (24.64 °C), at Cape Begur (24.47 °C), and in Valencia (23.47 °C). Along the Catalan coast and in Barcelona, water warmed to 24.2–24.5 °C by late May.
The warming was particularly noticeable in the north: all the buoys off the coasts of Galicia and Cantabria recorded record values. These include stations in Bilbao, Pasajes, Gijón, and Langosteira. Of the 15 deepwater buoys, 12 set new records, and of the 14 coastal ones, 6 did so. As Puertos del Estado notes, such a widespread and early rise in water temperature has never been observed in the entire history of monitoring.
Experts emphasize that the ocean responds to atmospheric changes more slowly than land due to its high thermal inertia. This means that even after the heat subsides, abnormally warm water can persist for weeks, creating conditions for marine heatwaves. The consequences affect not only nature but also the economy: temperature changes impact the distribution of marine species, increase ecosystem stress, and may affect fisheries.
Puertos del Estado operates one of the largest marine observation networks in Europe: 15 deep-water and 14 coastal buoys, 46 tide gauges, and a network of high-frequency radars allow real-time monitoring of temperature, waves, water levels, and currents. According to the World Meteorological Organization, there is a high probability of new temperature anomalies in the coming months, and the Mediterranean is considered one of the most vulnerable regions to warming.
Sea warming is not the only factor affecting summer vacations and lifestyle in Spain. For example, travel and camper living expenses turned out to be higher than expected, as shown by the experience of one blogger: a detailed breakdown of vanlife expenses reveals unexpected nuances of the Spanish summer.
Judging by current data, the trend of sea warming in Spain is becoming increasingly evident and requires close attention—both from specialists and everyone connected to the sea and the coast.
