As temperatures soar across the UK this week, health experts are warning that the ongoing heatwave could turn deadly, especially for vulnerable groups. A new study estimates that nearly 570 people could die from heat-related illnesses this weekend. The real-time analysis was carried out by scientists from the London School of Hygiene and Tropical Medicine and Imperial College London. Their model combines current weather forecasts with health data to estimate how many people might lose their lives due to high temperatures.
According to the research, around 303 deaths are expected across the weekend. Saturday is predicted to be the deadliest day, with 266 heat-related deaths, nearly half in London alone.
“Our study should be taken as a warning,” said Malcolm Mistry, one of the researchers. “Temperatures in the high-20s or low-30s may not seem dangerous, but they can be fatal—especially for older adults, infants, pregnant women, and those with existing health problems.”
This is the first real-time heat death estimate of 2025 and is based on health and weather data from nearly 35,000 neighbourhoods across England and Wales.
The situation is part of a larger trend across Europe. In Germany, heat warnings have been issued for much of the west and north, including cities like Frankfurt, Cologne, Hamburg, and Berlin. Meanwhile, France is experiencing an early heatwave, with Meteo France forecasting temperatures as high as 39 degrees Celsius in the west. Orange-level heat alerts, urging people to be “very vigilant” have been issued in several regions, including Rhone and Isere.
Experts say that one of the biggest challenges in understanding heat-related deaths is that they often go unrecorded.
“Many people who lose their lives in heatwaves rarely have heat listed as a cause of death,” explained Dr Garyfallos Konstantinoudis from Imperial College London. “But the high temperatures can worsen existing conditions like heart disease, asthma, or diabetes.”
Health authorities in the UK have already issued several warnings this week, urging people to stay indoors during peak heat, stay hydrated, and check on elderly or sick neighbours.
A separate report published on Friday added to the concern. Researchers from Imperial College London and the World Weather Attribution group found that climate change is playing a clear role in worsening heatwaves.
Before industrialisation, a heatwave like this may have happened once every 50 years. Today, it could occur every five years, thanks to rising global temperatures caused by human activity.
“Heatwaves are becoming more frequent and more dangerous,” the study said. “What we’re seeing now used to be rare, now it’s becoming normal.”
As the UK heads into the weekend, the message from scientists is clear: Take heat warnings seriously, especially if you’re caring for vulnerable people. While sunny weather might seem harmless, the consequences can be deadly.
