LONDON — The UK provisionally recorded its hottest June day on record on Thursday afternoon, with temperatures reaching 36.7 degrees Celsius in Merryfield, Somerset, the Met Office reported. At least 101 million Europeans faced temperatures exceeding 35 degrees Celsius.

In London, the Ambulance Service responded to its highest number of life-threatening emergencies on record on Wednesday. The service observed a 50% increase in calls for life-threatening emergencies compared to a typical Wednesday in June, and cardiac arrests rose by 30%.

Craig Harman, Chief Operating Officer of the London Ambulance Service, advised the public to take precautions. "I'm saying to people I need you to drink water even when you're not thirsty, staying out of the sun during the hottest parts of the day, and particularly not exercising outside and putting your body under additional heat and strain," Harman said.

Several hospitals declared critical incidents, leading to operational changes. University Hospital Southampton canceled planned operations and some outpatient appointments. Queen Alexandra Hospital in Portsmouth and Norfolk and Norwich University Hospitals NHS Foundation Trust also declared critical incidents on Wednesday. Firefighters in Derbyshire addressed a 500 square meter wildfire on Tintwistle Moor on Thursday evening. A hosepipe ban was implemented in Kent, and some schools and nurseries were forced to close.

Beyond England, Wales recorded its hottest June day on record on Thursday, with 35.9 degrees in Cardiff. Northern Ireland matched its previous record high for June, reaching 30.8 degrees in Castlederg.