Spanish weather agency confirms: Clear increase in the number of heatwaves in Spain

by Lorraine Williamson
increase in heatwaves

MADRID – The national weather agency Aemet emphasises the worrying increase in the number of heatwaves since the 1970s in Spain. This is what the meteorological institute says in response to the third heatwave of this summer about to start. 

Unusually high temperatures are expected from Monday (today) until the end of the week. Figures from Aemet show that during the summer months the Iberian Peninsula, the Balearic Islands and the Canary Islands regularly experience such heat periods. With the announcement of this new heatwave, the number of extreme heat episodes of last summer is equalled, namely three. However, the hottest month of August has only just started. 

The data goes back to 1975. Furthermore, it is noticeable that in the 1980s and 1990s, there were years without any heatwaves. Meanwhile more recently there are sometimes two or three heatwaves per summer. 

When is there a heatwave? 

Aemet points out that defining a heatwave is complex because there is no uniform definition. In Spain, where climatic differences between provinces are large, Aemet uses the following definition: “A heatwave is a period of at least three consecutive days, during which at least 10% of the monitored measuring stations record maximum temperatures above the 95th percentile of their daily maximums in July and August covering the period 1971-2000”. These criteria will be met in the coming days in the southern part of the peninsula, with more than 20 provinces on heat alert. 

Most intensive and prolonged heatwaves in recent years 

Historical data shows that the most intensive and prolonged heatwaves have occurred in recent years. In July last year, a heatwave lasted no less than 18 days and affected 44 provinces. Similar situations occurred in 2022. Furthermore, it is necessary to go back to 2015 to find an even longer heat wave. It lasted from June 27 to July 22 and affected 30 provinces. However, by comparison, there were no heatwaves in 1996 and 1997. 

Weather agency response to climate denier 

Climate deniers never seem to give up, but Aemet has responded to one on Twitter. The Twitter user claimed that warm nights are not new and compared the temperatures of 2012 with those of this summer: “In 2012, during the night of August 2 to 3, temperatures did not fall below 27 to 25ºC. That was 13 years ago, but nights with 27ºC are now supposedly new.” 

Aemet offered the Twitterer a factual rebuttal to his claim: “Hello @sisopuerto. In 2012 we had 5 extremely hot nights in Valencia, with the warmest night on August 11 having a minimum temperature of 25.4ºC. In 2023, so far, we have already had 21 such nights in Valencia. That´s more than the total recorded between 1940 and 1999, and four times as many as in all of 2012.” 

Furthermore, from their account for the Valencia region, Aemet pointed out that not only is it a hotter summer than that of 2012, but with August still ahead, Valencia has already had nine hotter nights than the hottest night of 2012. The night of July 20, with a minimum of 27.5°C, is the warmest July night ever recorded in Valencia. 

Further, Aemet commented, “Have you felt that this month has been very humid and that you were constantly sweating? The data confirms the air masses that passed over us in July are the most humid in the historical series.” Many Twitter users praised Aemet for this response and took the opportunity to criticise climate deniers who “continue to deny obvious facts”. 

How long will the current heatwave last? 

This current heatwave is likely to last until Friday or Saturday, according to the Aemet. Temperatures above 40°C could also be reached during this period in northern areas, and even 44°C in central and southern parts of the peninsula. At night, the mercury will not fall below 25°C in certain parts of the country, particularly in the Mediterranean and inland cities. 

The Canary Islands will also not be spared, where temperatures of over 34°C or 36°C are expected in mountainous areas and also on Fuerteventura in the second half of the week. If the forecast is correct, this will be the third heatwave of this summer, following the two previously recorded heatwaves in July. 

Related: Tips for sleeping well during a heatwave 

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