The UK experienced a “tropical night” on Monday as the record for highest daily minimum temperature in May was broken for the second consecutive day.Temperatures did not fall below 21.3C on Monday at Kenley airfield, in south London, after the UK recorded its hottest May day since Met Office data began, the forecaster said.The country also recorded its provisional all-time hottest meteorological spring temperature when Kew Gardens, in south-west London, hit 34.8C on Monday. The previous all-time May peak stood at 32.8C, reached in 1922 and 1944.The Met Office said 12 locations broke records on Monday – ranging from Suffolk to Berkshire to Warwickshire – and 97 of its monitoring sites reached or surpassed 30C.The UK’s previous warmest May night was Sunday, when temperatures did not fall below 19.4C at Kenley airfield.“We have provisionally broken the UK record for highest daily minimum temperature in May … again,” the forecaster said.“Temperatures didn’t fall below 21.3C overnight at Kenley airfield, making it a ‘tropical night’ [no lower than 20C],” it added. “Remarkably, the record was also broken yesterday.”Bournemouth beach on Monday. Photograph: Simon Ackerman/Getty Images“In the past, heatwaves built and built and built and built over days and days and days, these now just develop so quickly,” the Met Office senior forecaster Greg Dewhurst said on Monday, adding that the climate crisis was boosting the heat.On Tuesday, highs of 35C were expected for large swathes of southern England and Wales, which could reach near 36C, a Met Office meteorologist said. Those forecasts covered the Midlands, as well as south-east and south-west England, East Anglia and south Wales.Many places across England and Wales would reach the heatwave threshold on Tuesday, with some having experienced it for five days by Wednesday, said the Met Office meteorologist Becky Mitchell. There may be thunderstorms in the afternoon, affecting high temperatures.Temperatures must meet or surpass a specific threshold for three consecutive days to be classed as a heatwave. For this time of year, the highest heatwave threshold in the UK is 28C, applied to London and north of the capital towards Cambridgeshire.In eight parts of England, those conditions were already met by Sunday evening, including in Heathrow, Kew Gardens and Northolt, in London, and locations in Oxfordshire, Suffolk and Essex. The figure was anticipated to be higher after the bank holiday weather, however data was not yet available.With nearly 100 sites having reached 30C on Monday, it “goes to show how many places would have succeeded their heatwave threshold”, said Mitchell.Temperatures will gradually decline from midweek but will remain in the high 20s, with dry, sunny spells expected.On Monday, fire and smoke spread across a large patch of Holyrood Park, near Arthur’s Seat in Edinburgh. Emergency services were alerted at about 6.50pm on Monday to the blaze, which started in vegetation near the ruins of St Anthony’s chapel.Two fire engines remained at the scene at 6.30am on Tuesday, with firefighters having worked through the night to tackle the blaze. Clouds of smoke could be seen rising from the area and residents were advised to keep their windows and doors shut as a precaution.In Spain and France, more new highs were likely to be set on Tuesday as the heatwave continued across Europe.The risk of unnaturally hot extremes has risen with average global temperatures, which have been pushed higher by a blanket of carbon pollution smothering Earth.Gareth Redmond-King, of the Energy and Climate Intelligence Unit, a thinktank, said: “Scientists are clear that cutting those emissions to net zero is the only way to halt climate change and limit the danger. But we also know we’ve got more extreme heat coming this year if, as expected, El Niño joins forces with climate change to break more heat records.”He added: “The Climate Change Committee was clear last week that alongside cutting emissions to net zero, adapting to our already warmed climate is far less costly than dealing with its ever more dangerous impacts.”