If you travel to Alacant, Murcia or Valencia today, don't expect that taking a bath will refresh you. The water will be at 30ºC on the beaches of Dénia, Xàbia, Cartagena or Malvarrosa, while outside, on the sand, the maximum will be between 29 and 31ºC. What does this mean? That today on the Malvarrosa beach, in the Valencian capital, in the water, the temperature will be higher than outside.
Neither expect it in the Balearic Islands, Castelló or Tarragona, where the sea will be at 29ºC. On Caldetes beach (Maresme) the water will be at 28ºC, and if it drops further south, in l'Arenal, in l'Hospitalet de l'Infant, the forecast indicates 27ºC, two degrees less than in Benicassim, in Castelló. In reality, today there is no beach where you can bathe at less than 25ºC on all the strips of the eastern peninsular coast; although if you are satisfied with this temperature, you can visit those of the Girona regions.
The temperature at the buoy in the port of Barcelona was 27.3ºC yesterday, so the record in the sheet of water near its beaches would be somewhat higher, since the temperatures near the coast are a little higher. In Tarragona, if it's not windy, it's "like getting into a hot tub", say the meteorologists
The water in the Spanish coastal areas reached an average of 24.6 °C in mid-July, which is about 2.2ºC more than normal for this time of year. This is indicated by the State Meteorological Agency (Aemet). The measurements refer to average temperatures both on the Mediterranean and Atlantic coasts.
On these dates, "the records of the two previously warmest years" are being exceeded; this is 2015 (when 24°C was reached) and 2022 (23.7°C), according to Aemet. This situation does not have "precedents in mid-July in the entire historical series", which began in 1940.
In the same way, the Gulf of Leon (in waters between France and Spain) has reached abnormally high levels, specifically three degrees above average.
All this situation, in a context of global warming of the oceans, has been considered especially "worrying" by Rubén del Campo, Aemet spokesman, since summer is far from over. The forecast is that this warming of coastal waters will continue in the coming weeks, according to José Luis Camacho, also Aemet spokesman.
The culminating point of this warming does not necessarily coincide with the heat wave, but rather "it will be delayed." "The peak of the sea water temperature will be reached at the end of August, so the forecast is that we still have a month for it to continue rising," he says.
“The Mediterranean already shows a clear tendency to warm up; but this year the Bay of Biscay and the Cantabrian coast have warmed up a lot”, points out José Luis Camacho. In these areas of the Atlantic there have been heat waves, which is one of the characteristics that best define the months of June and July of this year. The warming has not only occurred in the Bay of Biscay, but throughout the North Atlantic.
Normally, the measurements of the waters of the coast are not made next to the beach, but rather they are captured by making a short journey by boat, they are taken in buoys (at variable distances from the coast) or they correspond to some installation of the ports, where these measurements are made.
The weather situation in the area in question influences the dynamics of the water temperature on the coast as a basic factor, but in second place the currents and the upwelling of deep water, which is much cooler, have an impact.
This in turn depends on the type of coast. If the waters are shallow, as is the case in Tarragona, the water heats up enormously.
This could explain, for example, that, unlike areas such as the Ebro delta, in areas of the Galician coast deep waters can emerge and it is the case that on a hot day in Galicia and with a wind from the land, the water on the beach can be at 19 degrees.
In Spain, in general terms, the bathing waters with the highest temperatures occur in the Balearic Islands or Murcia, while the greater the proximity to the Strait of Gibraltar, the greater the probability of outcrops of colder waters. “The current comes from the Atlantic, which, together with the winds from the land, causes the bottom water to rise,” adds Camacho.
