Updated Jul 19, 2022 - World

Historic U.K. heat wave pushes temperatures past 40°C for first time

A heat warning sign at a train station in London.

A heat warning sign at a train station in London. Photo: Justin Tallis/AFP via Getty Images

In the midst of an unprecedented heat wave, the U.K. on Tuesday broke its national record for the highest temperature ever registered, with a provisional reading of 104.36°F (40.2°C) at London's Heathrow Airport, according to the country's weather service.

Why it matters: This is the first time the U.K. has breached this temperature that is more common in tropical and desert climates, and studies point to climate change as a key factor behind the scorchingly hot temperatures.

  • Heat waves of this magnitude and duration can be deadly, and pose particular health risks to vulnerable groups like the elderly, those with preexisting medical conditions and anyone without access to cooling.
  • Only about 3% of homes in the U.K. have air conditioning.

Driving the news: The U.K. Met Office warned that temperatures are expected to keep rising throughout the day. Multiple other locations have exceeded the 40-degree mark as well, including within the city of London.

  • The previous national temperature record, set in 2019, stood at 101.66°F (38.7°C). A provisional total of 34 weather stations broke that record on Tuesday, the Met Office reported.
  • According to climate scientist Simon Lee, 3 of the 4 hottest days in U.K. history have occurred during the last 4 years.

Context: Studies have shown that climate change is making heat waves like this one hotter than they otherwise would have been, as well as more frequent and longer-lasting.

What they're saying: "I wasn't expecting to see this in my career but the UK has just exceeded 40°C," said Met Office chief of science and technology Stephen Belcher. "For me, it's a real reminder that the climate has changed and it will continue to change."

  • "Research conducted here at the Met Office has demonstrated that it's virtually impossible for the UK to experience 40°C in an undisrupted climate," Belcher said.
  • "But climate change driven by greenhouse gases has made these extreme temperatures possible."
  • Belcher said under a high emissions scenario, the U.K. could see 40°C temperatures every three years.

The big picture: The provisional new temperature record comes on the back of the U.K.'s warmest night on record.

Meanwhile... The heat has also sparked massive wildfires in France, Portugal and Spain and forced thousands of people to flee their homes. Fires broke out Monday in the UK, including in populated areas.

  • More than 1,100 people have died in Spain and Portugal from heat-related causes since the heat wave began.
  • The toll in France and the U.K. is not yet known, and may not be for several more weeks to months due to the difficulty of counting excess heat-related fatalities.
  • On Friday, the U.K. Met Office issued its first-ever "red" extreme heat warning, indicating a national emergency due to the risk of "serious illness or danger to life."

Go deeper: Experts saw Europe's devastating heat wave coming

Editor's note: This article has been updated with new details throughout.

Go deeper