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.