The Cantabrian Sea has broken records on the Basque coast, warmed up above 26 ° C

Anyone who had bathed in the waters off the Basque coast this summer would have noticed that the sea was particularly hot; it did not seem like the Cantabrian Sea, but rather the Mediterranean. In this summer weather season (June-August) the average temperature of sea surface water has been 23.4 ° C, 1.7 degrees more than usual in the last decade.

However, there have been days when temperatures have far exceeded these figures, reaching 26 ° C; on 17 August this year, the State Ports buoy off Cape Matxitxako recorded a record temperature of 26.1 ° C. The previous highest mark in the area was on 14 July 2018 at 25.5 ° C.

This year's records have surpassed all recent historical records, and July has been a milestone, with thermal anomaly 2.1 ° C higher than the average of the last decade.

In 2026, moreover, the temperature of water on the Basque coast has warmed earlier than usual. According to the data analysed, in May, the average temperature rose to 17.4 ° C (in 2017 it was 15.7 ° C) and in April the absolute peak never seen reached 17 ° C.

The sea doesn't cool

Temperatures this summer have been very high: the second warmest since at least 1970, according to the Basque Meteorology Agency, Euskalmet, after 2003. The sun has heated the sea a lot, and after sunset the water has not even been able to cool down: in 68% of summer nights, the water temperature exceeded 23 ° C, and in 9 of them it did not fall from 25 ° C.

The hottest night was the morning of August 17th from 00:00 to 06:00, the minimum water temperature was 25.5 ° C.

Heat waves, even at sea

These high temperatures recorded in our waters have not been a one-off phenomenon. The warming periods have continued over time, so that this summer we have had three aerial heatwaves (to which must be added another one from May), and two at sea.

The first incident was 16 days (from 18 June to 3 July) of "moderate" intensity, with an average anomaly of 2.3 ° C over normal values.

The second heat came immediately: five days, the sea entered a second heat wave, which was "severe." It lasted for 50 days, from July 9 to August 27, and for several days there were anomalies of about 3 ° C.