A leading health expert has warned that Britain's soaring temperatures are "not just another heatwave" as the UK braces for what could become the hottest June day ever recorded. The Met Office has issued a rare red warning for extreme heat covering parts of England and Wales from Wednesday morning (June 24) through to Thursday night (June 25), with temperatures forecast to reach 39C and potentially beating the UK's all-time record of 40.3C.
What is driving the extreme heat?
Forecasters say a "heat dome" sitting over western Europe is driving the extreme conditions, with temperatures expected to top the current June record of 35.6C, set in Hampshire during the historic summer of 1976. Met Office spokesman Grahame Madge said temperatures could peak at around 39C in London or the South East on Thursday, with even higher temperatures remaining a possibility. He added: "It is important to remember that the temperature value is only one element of this extreme heatwave story. The other major factor is the high humidity which for many will make the intense heat even harder to endure."
Impacts on schools and transport
The warning comes as hundreds of schools across southern England announce closures and transport operators slash services. Emergency services have also been forced to deal with thunderstorms, flooding and lightning strikes triggered by the unstable weather, with Somerset having "around 18,540 strikes in the past 24 hours," the Met Office said.
Health experts warn NHS is unprepared
Dr Alan Dangour, director of climate and health at Wellcome, said the heatwave should be viewed as a threat to public health. He said: "As the UK gets a rare red heat health warning, this is not just another heatwave - it's a growing health threat fuelled by climate change. And the NHS is not yet prepared for this new reality. Vulnerable people like pregnant women are already facing higher risks, including premature birth, during heatwaves. Simple, practical measures - like keeping maternity wards safely cool and ensuring midwives have clear guidance - could make an immediate difference. The health impacts of climate change are already here, and we have an opportunity and responsibility to better protect those most at risk."
Tropical nights add to the danger
Nine areas across England experienced what the Met Office classifies as a "tropical night" overnight, with temperatures failing to fall below 20C. Scientists say warm nights can be just as dangerous as high daytime temperatures because they prevent the body from recovering from heat stress. Dr Laurence Wainwright, from the University of Oxford, warned that the UK is particularly vulnerable because people and infrastructure are not adapted to prolonged periods of extreme heat. He said: "When a 35C day - historically very rare in this country - suddenly appears, this is a shock to the system. Our bodies – especially our brain and heart – struggle, simply because they are not used to it and have to devote most of their energy and effort to stay cool." He added that tropical nights can make "a good night's sleep all but impossible for most", which can lead to a drop in work performance and productivity, an increase in accidents, lower school test scores, a decline in mental health, worsened cognitive function, and an increase in impulsive behaviours.
Climate change link
Climate scientists have also warned the latest heatwave is another sign of a warming planet. Professor Hayley Fowler, Professor of Climate Change Impacts at Newcastle University, said the current heatwave "has almost exactly the same atmospheric circulation set up" as the UK's record-breaking 40C temperatures in July 2022. She said: "Heatwaves are becoming more frequent, longer and hotter with climate change, as a direct result of the fossil fuels we are releasing as a society." Prof Fowler added: "We can expect to have to cope with more and more of these types of events in the years to come. Our current climate is the least extreme we will live in in our lifetimes, and certainly until we reach Net Zero, and we need to adapt urgently to live and work in these extreme temperatures."
Advice for staying safe
Experts are urging people to stay hydrated, avoid strenuous activity during the hottest part of the day, keep homes shaded where possible and check on elderly relatives, neighbours and other vulnerable people. Dr Neil Maxwell, from the University of Brighton's Environmental Extremes Lab, said: "One of the biggest mistakes people make is trying to carry on as normal. During periods of extreme heat we need to adapt our expectations and behaviours. As our climate continues to warm, these are skills that will become increasingly important for all of us."
