In the Mediterranean it no longer makes sense to talk about a “tropical night” because almost all of them are.

On June 21, the thermometer at Almería airport did not drop below 30.8ºC throughout the night. In fact, at seven in the morning the temperature was exactly the same as it would have been on an August afternoon twenty years ago. It seems like an isolated event (after all, it is the first time that we have encountered a minimum like this in the Mediterranean in June), but it is not.

Just a handful of days later, the AEMET experts made it quite clear: it no longer makes much sense to talk about “tropical nights” in the Mediterranean because almost all summer nights already are. That is, almost no drops below 20 degrees.

The June heat wave was (quite) exceptional. Not only because the 22nd and 23rd were the warmest June in the country since at least 1950; nor because the average peninsular anomaly was 7.1 ºC. The most striking exceptionality occurred in the early morning: according to the same AEMET24 of its 86 main stations marked the highest minimum in the historical series.

That was the symptom.

But the problem is another. A problem that has to do with an indicator that jumps so much that it has stopped meaning something just when we need it most. Or, at least, when we are most aware of the lack of it.

In 2025, A CSIC research team published a work in Environment International in which he analyzed 178 cities, separating the effect of warm nights from that of warm days. Their conclusions indicate that nocturnal heat is associated with an increase in mortality of up to 3% and that this effect is independent of daytime heat.

The mechanism is also dramatically simple: if the early morning does not ease, the body does not recover, sleep is degraded and cardiovascular or respiratory pathologies worsen rapidly.

Why should we care? Because southern Europe is among the regions hardest hit by temperature changes.

But there is something else: the same CESIC studyexcess mortality due to nocturnal heat in Spain is concentrated in the interior (Granada, 3.56%; Madrid, 3.45%; or Córdoba, 3.44%) while the Mediterranean coast is holding up much better (Barcelona, ​​0.56%; Alicante, 0.55%; or Almería 0.46%).

That is, the problem is adaptability to these types of phenomena. Something in which the coast wins because it has been suffering from it (to a lesser extent, but suffering from it) for many years.

The future we are going to. AEMET projects to go from the current 22 heat wave days per year to 47 at the end of the century with intermediate emissions. Preparing is no longer an option if we don’t want to. paint the windows of half the country with chalk or white yogurt.

Image | Christian Van Der Henst

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