A Mediterranean summer, as told by the sea
What do June and July reveal about one of the most persistent marine heatwave seasons on record? With sea surface temperatures reaching up to 3°C above average – and still counting – three of the past five years have already experienced conditions that would once have been considered exceptional, like those of the record-hot summer of 2003. By early August, one thing is already clear: marine heatwaves are no longer isolated events – they are becoming a persistent feature of Mediterranean summers. This week, we look at the season at sea through CMCC’s Mediterranean Forecasting System.
The summer of 2026 is being shaped by headlines about record-breaking air temperatures, prolonged heatwaves, and devastating wildfires. Red heat alerts have become routine in cities across Italy, while major wildfires have swept through France, Spain, Greece and the Balkans, and persistent drought is affecting large parts of western and central Europe.
But another story has been unfolding, out in the waters of the Mediterranean Sea.
As we enter August, observations from the CMCC Mediterranean Forecasting System (MedFS) already allow us to draw a first picture of the season at sea. Looking at June and July, one message clearly emerges: this has not simply been a summer of exceptionally warm waters, but a summer of persistent and recurring marine heatwaves across much of the Mediterranean basin.
As of early August, the latest MedFS observations show that much of the Mediterranean remains under marine heatwave conditions.