Winter has traditionally been the most deadly season in the UK. But that is changing, thanks to searing summer heatwaves, with the number of heat-related deaths in England and Wales each year now rivalling deaths from cold weather.
Across England and Wales, just over 40,000 more people died on the hottest days between 1988 and 2025 than would be expected under normal temperatures, new figures released today by the UK’s Office for National Statistics (ONS) show.
By comparison, across the 37-year period, almost 139,000 deaths were associated with the coldest days.
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But as summer temperatures rise, the number of heat-related and cold-related deaths each year is starting to converge, the ONS said.
In 1992, hot weather was associated with the deaths of 722 people, compared to 3412 deaths for cold weather. By 2023, hot weather was linked to 2234 deaths in England and Wales, with cold weather during the same year linked to 3294 deaths.
The ONS estimated deaths associated with the coldest 2.5 per cent and hottest 2.5 per cent of days between 1988 and 2025, accounting for other factors such as air pollution.
A series of hot summers, fuelled by a warming climate, has driven the trend in rising heat deaths. All five of the UK’s warmest summers on record have occurred since 2000, with 2022 being the first summer to record a 40°C day in the UK. Deaths associated with hot weather have been rising since 2011.
The ONS data didn’t include 2026 in its assessment, but prolonged high temperatures and successive heatwaves mean England is widely expected to log a record number of heat-related deaths this summer. In July, the UK’s Health Security Agency (UKHSA) said heatwaves in May and June 2026 had caused 2877 heat-associated deaths in England, almost double the entire 2025 total. That is also higher than the total number of deaths associated with cold weather in England during winter 2024-25, which the UKHSA has at 2544, raising the possibility that heat-related deaths in 2026 could outstrip cold-related deaths for the first time on record.
Summer heat is “now killing almost as many people as winter cold each year in England and Wales,” said at the Grantham Research Institute on Climate Change and the Environment in London in a statement. “The deaths during the record heat of summer 2026 may be higher than the mortality we experienced last winter.”
at the University of Surrey says the gap between hot weather deaths and cold weather deaths is “narrowing a lot quicker than anyone anticipated it would”. Without action to help people better cope with high temperatures, we will see “high and rapid growth” in the number of hot weather deaths in the UK over the coming years, he warns.
Climate change is expected to bring even hotter, drier summers to the UK, further increasing the public health risk. Already, more than half of UK homes are at risk of overheating during hot weather – that is projected to rise to 92 per cent by 2050, according to the UK’s Climate Change Committee.
