The UK has recorded its hottest day of the year so far with a provisional temperature of 38.1C in southern England as Europe sweltered under a major heat dome.As temperatures on the continent approached 40C at the peak of the summer’s fifth heatwave, the thermometer at Kew Gardens in west London surpassed the previous high of 38C on 28 June, the Met Office said.In France, which has recorded 17 days of extreme heat – one of the longest periods ever – Bordeaux and Nantes recorded 38C, Paris 36C and Montpellier 34C.Temperatures were expected to hit highs of 40C in Spain and 41C in France later on Thursday, triggering fresh fears of wildfires in the two countries.A plane drops retardant over a wildfire in Aznalcollar, Spain Photograph: Marcelo del Pozo/ReutersIn the UK, Charlwood in Surrey recorded 37.1C, the second highest August maximum temperature since 2003. Teddington in London reached 36.1C Pershore College in Worcestershire36C and temperatures in Wales reached 35C, according to provisional Met Office figures.An amber extreme weather warning was issued on Thursday across east and south-east England, including London, the Midlands, north-west England, south-west England and parts of Yorkshire and Humber.An extreme heat alert warning of significant impacts to health and social care services across the whole of England is in place until 9pm on Friday.mapThe Met Office has said this summer is on course to be the UK’s hottest since records began, with 2026 likely to be the first year in which the country has recorded four separate days with temperatures of 36C or above.Spain has broken its burned area record for this time of year, data published by the European forest fire information system on Thursday shows, while in France, the area burned by the third week of July already surpassed that of any full year on record. Fire weather in the EU since the start of the year has been more severe than ever before.