Sea temperatures off the coast of Alicante have risen by five degrees in just two weeks, reaching 23.8°C, according to data from the State Ports buoy network. In mid-May, the water was below 19°C. Experts say the current surface temperature is more typical of August, although climate change has brought similar values forward into early summer in recent years.

The Climatology Laboratory at the University of Alicante says the western Mediterranean is recording unprecedented temperatures for late May. A very hot air mass over south-west Europe and weak winds have accelerated warming at sea. In some parts of the Balearic Sea, temperatures are forecast to sit up to 6°C above average.

As a result, specialists warn that tropical nights – when temperatures do not fall below 20°C – are likely to become frequent along the coast for the rest of the summer. Alicante recorded 106 tropical nights last year, a record high, and experts say figures close to 100 nights are possible again.

Meteorologists also warn that a warmer Mediterranean stores more energy, increasing the risk of more intense downpours in autumn. While occasional strong winds could still cool surface waters, scientists say the long-term trend remains worrying.