A so-called "heat dome" of warm air from northern Africa trapped under a high-pressure system over western Europe is behind the high temperatures not usually seen until high summer.Temperatures in Spain were expected to peak later this week at 38C, while parts of Italy imposed restrictions on working outdoors.In the UK, the Met Office weather agency said it was the hottest May day on record, with temperatures hitting 34.8C at Kew Gardens, southwest London -- a full two degrees above the previous high."This heat would be exceptional in the UK even in mid-summer, let alone May," it said on X."The weather here, it's like a mini version of hell. It's boiling. It's like really hot," said 10-year-old Liza Nizari on a visit to London, where temperatures normally average about 17C or 18C at this time of year.Lindy Brand-Daloze, a 66-year-old Australian administrator who has been living in in London for 12 years, said: "It's warm, but it's climate change, isn't it? So, you know, (we have) probably got to get used to this."Scientists say human-induced climate change is making extreme weather events like heatwaves, droughts and floods more intense, resulting in temperature records being broken more frequently.Met Office meteorologist Greg Dewhurst told AFP the increase in extreme temperatures was "a good indication of climate change in action" and more likely to become "the new norm".Climate advisers last week warned the UK government that the country was "built for a climate that no longer exists" and urged it to adapt infrastructure like schools and hospitals for a warming planet.In 2022, temperatures in the UK soared above 40C for the first time since records began.Heatwave alertAcross the Channel, weather agency Meteo-France put eight areas in the west of France on heatwave alert -- signifying three days and nights of intense heat that are likely to pose a health risk to the population.