Spain is in the grip of its first heatwave of the year, with temperatures in parts of the west and south expected to reach 44C (111.2F). Heatwaves – defined as at least three consecutive days of temperatures above the average recorded for July and August from 1971-2000 – are becoming more frequent and are beginning earlier, according Aemet, the Spanish meteorological office. “We are facing unusually high temperatures for June,” said Rubén del Campo, an Aemet spokesperson. The heatwave, the result of the anti-cyclone Alex and a mass of very hot air over north Africa, is expected to last at least until Tuesday and is the third earliest on record. The last time a heatwave arrived this early was in 1981. It follows the hottest May on record, with temperatures last month three degrees above average. Aemet calculates that global heating means Spain’s summer begins between 20 and 40 days earlier than it did 50 years ago. There have been 10 June heatwaves since 1975, five of them since 2011 and, assuming this one lasts three days, over the past 12 years there will have been a heatwave in June every two years. Last year was Spain’s hottest and driest on record, with temperatures hitting an all-time high of 47.4C in Montoro in the southern province of Córdoba. Overall, across the country the average temperature was 0.5C above the average for 1981-2010. And 2021 was not a one-off but the latest in a series of hot years. “For the first time we’ve seen eight consecutive years with above-average temperatures,” Del Campo said. “There is a clear trend towards things getting hotter.” These hot years have not been matched by cold ones. Over the past 10 years, only 14 exceptionally cold days have been recorded, compared with 146 exceptionally hot ones. With little time to acclimatise to what would normally be midsummer temperatures, people are at greater risk of heatstroke, dizziness and headaches. It will also be harder to sleep, with night-time temperatures of 25C – officially “torrid nights”, according to Aemet – or in some areas 30C, known as “infernal nights”. A study carried out last year in cities in Spain, Portugal, France and Italy revealed a link between mortality and high night-time temperatures. Spain’s department of health has warned people to stay indoors as much as possible and to avoid exercise during the hottest part of the day. People are also urged to drink plenty of water and avoid alcohol.