The record for the hottest May day has been broken again, with temperatures climbing to 35C in London as a heatwave sweeps the UK.Temperatures on Tuesday surpassed Monday’s provisional all-time hottest meteorological spring temperature of 34.8C recorded in Kew Gardens in south-west London.In a post on X, the Met Office said: “Today is now the hottest day in May on record with Heathrow and Kew Gardens provisionally reaching 35.0C.“Until yesterday the highest temperature in May was 32.8C, but we’ve now exceeded that record on consecutive days by a full two degrees Celsius.”The forecaster said that highs could creep up to 36C across large swathes of southern England and Wales, after days of high temperatures over the bank holiday. Four teenagers, including three boys and one girl, as well as one man in his 60s, have all died in “water-related incidents” in recent days. Yellow weather warnings for thunderstorms have been issued between 3pm and 10pm for parts of the South West, West Midlands, East Midlands and East of England on Tuesday. The country also experienced a “tropical night” as the record for the warmest minimum temperature for May was broken for the second consecutive day.Sunbathers relax in the sunshine on Bournemouth beach on Tuesday (AFP/Getty)The UK Health Security Agency (UKHSA) said amber alerts for the South West, South East, London, East and West Midlands and the East of England will remain in place until 5pm on Thursday 28 May, along with yellow alerts for the North West and North East.Speed restrictions are also in place on LNER routes which are causing delays, with services limited to 20 mph on 125mph lines at St Neots, Cambridgeshire, and Tollerton, North Yorkshire. South Western Railway (SWR) said “smoke was reported on the track” between London Waterloo and Vauxhall stations, and Great Northern passengers faced delays due to damage to overhead electrical wires. Heatwave conditions were already met in eight parts of England by Sunday night: Heathrow, Kew Gardens and Northolt in London; Benson in Oxfordshire; Brooms Barn and Santon Downham in Suffolk; High Beech and Writtle in Essex.That number will be higher after the bank holiday weather but the data is yet to be released, Ms Mitchell said.To qualify as a heatwave, temperatures must meet or surpass a specific threshold for three consecutive days.Temperatures could reach as high as 36C in parts of southern England (Getty)Temperatures will start to gradually decline from the middle of the week but it will still be largely dry with sunny spells.Many will still experience temperatures in the high 20s.However, they will lower by around 10C in eastern areas as a brisk easterly wind develops.If validated, the latest May record means seven of the 12 monthly highs have been set since 2003, the Met Office said.A previous study by the forecasters found breaking that record “is around three times more likely now in our current climate than it would have been in a natural climate not impacted by greenhouse gas emissions”.This means that the event once judged a one-in-a-100-year event is now a one-in-33-year event, it said.People relax in the sunshine beside the Regent's canal in London (AFP/Getty)Amid the bank holiday heat, firefighters worked through the night to tackle a grass fire near Arthur’s Seat in Edinburgh as temperatures in the city hit 25C.Clouds of smoke were seen rising from the area around the natural landmark and local residents were advised to keep their windows and doors shut as a precaution.On Monday, a 13-year-old boy also died after getting into difficulty in a West Yorkshire reservoir.West Yorkshire Police said the teenage boy was pulled from the water and taken to hospital, where he was pronounced dead.A teenage girl was also pulled from the water at a country park in Kingsbury Water Park in north Warwickshire, and she was pronounced dead at the scene. Meanwhile, the AA warned that the interior of vehicles can reach 60C on a day when the outside temperature is 27C.Tourists walk across Westminster bridge buying and eating ice cream (AFP/Getty)The car rescue group said it attended 15 per cent more breakdowns between Friday and Monday than in the same period last year because “heatwave conditions put extra strain on vehicles”.The company was called out to 34,124 over the four days, compared with 29,602 during the same bank holiday period in 2025.The heat is considered to be dangerous for some vulnerable groups including older adults as their bodies struggle to regulate temperature.Age UK recommended staying inside during the hottest hours of the day, between 11am and 3pm, and having regular cold baths or showers.