An extraordinary early-season heat dome stretching across Western Europe is pushing temperatures to record-breaking levels this week, prompting life-threatening risk warnings for millions of people across the United Kingdom, France, Italy and Spain.
For only the second time in the U.K.’s history, national authorities have activated the highest-tier “red heat health” alert, covering most of central and southern England and all of Wales. The first and only previous red heat warning was issued just two years ago, in July 2022, when the country hit a historic milestone with temperatures crossing the 40°C (104°F) threshold. This week’s event marks the most intense June heatwave ever recorded in Britain, with the U.K. Met Office projecting a peak temperature of 38°C in southern regions. By Tuesday, temperatures already climbed to 34.6°C at a weather station in Wisely, a site located southwest of London, and overnight temperatures are forecast to stay far above seasonal averages through the end of the alert period on Thursday.
Mark Sidaway, the Met Office’s deputy chief forecaster, emphasized the severity of the unfolding conditions in a public statement. “Red warnings are reserved for the most severe events and we’re expecting severe and significant impacts from this heat wave, with health impacts likely for many, even beyond those who are normally more vulnerable to the heat,” Sidaway said. The extreme heat has already rippled through daily life across the U.K.: dozens of schools have shut their doors to protect students, widespread train service cancellations have upended travel plans, and officials have urged the public to avoid all non-essential travel in red alert zones.
Britain’s national rail operator Network Rail has enacted strict speed limits across most of England and Wales to prevent dangerous heat-related infrastructure failures, including buckled steel rails and sagging overhead electric lines that power passenger trains. Cross-border rail service Europlane has also scrapped four trains scheduled between London and Paris for Wednesday and Thursday, citing expected dangerous weather conditions. Even the centuries-old traditions of the British Parliament have bent to the heat: male journalists assigned to cover the House of Commons have been granted special permission to go without suit jackets in the press gallery for the day.
The heatwave’s impact extends far beyond British borders, with authorities across Western Europe scrambling to respond to dangerous conditions. France notched an all-time national high temperature record on Tuesday, breaking a new mark with a national average thermal indicator of 29.8°C (85.6°F) calculated from readings at 30 monitoring stations across the country. This new record marks just the latest in a string of unprecedented temperature highs that have hit Western Europe’s largest nation in recent years. In response to the heat, Paris’s most iconic tourist sites — including the Eiffel Tower and the Louvre Museum — cut visiting hours, while schools and public transit schedules were disrupted across the country.
In Italy, the national Health Ministry issued red emergency heat alerts for 16 major cities on Wednesday, including top urban centers Rome, Milan, Florence and Turin. Unlike lower-tier warnings, the “bollino rosso” red alert signals that extreme heat poses a risk to all people, not just groups typically vulnerable to high temperatures like the elderly and people with chronic illness. Forecasts call for temperatures to hit 41°C (105°F) in Florence and 38°C (104°F) in Milan, with Rome and Naples expected to reach highs just below 36°C (96.8°F).
Spanish and French authorities have also issued separate heat warnings for tens of millions of residents total, as the sprawling heat dome traps hot air across the region. Speaking Wednesday morning, Met Office meteorologist Alex Burkill warned that the worst of the heat was still to come for the U.K., saying, “If you think it’s hot already, well, we ain’t seen nothing yet.”