UKHSA estimates 2,877 deaths in May and June heatwaves

The UK Health Security Agency (UKHSA) estimated that 2,877 people in the country died in the May and June heatwaves, almost double the figure recorded across the whole of summer 2025¹. The estimate was reported by The Standard on 26 August 2026, which said the agency had made it the previous month¹.

A separate study by experts at Imperial College London, the Met Office and the London School of Hygiene and Tropical Medicine estimated there were 2,700 excess deaths in England and Wales over the same May and June heatwaves². In the capital, that study put the heatwave death toll at 109 in May and 344 in June, and stressed that in both months "warming was strongest in the urban heat island of Greater London"². The two estimates differ and the sources do not reconcile them.

Office for National Statistics (ONS) analysis cited by The Standard found that across England more than 40,000 extra people died on the hottest days between 1988 and 2025 than would be expected in normal weather¹. An estimated 0.36% of all deaths in London over that period were associated with days that saw the most sweltering temperatures, a higher proportion than any other region; the lowest figure was for north-west England, at 0.15%¹. The capital also saw the most deaths related to freezing weather, with cold-related mortality ranging from 0.88% of all deaths in London to 0.52% in north-east England¹.

The ONS said the London figure might reflect "certain socioeconomic factors that influence vulnerability to heat" that are more prevalent in the city, such as living costs and household overcrowding, which "may limit the capacity to adapt to high temperatures"¹. James Tucker of the ONS said:

The figures do not include deaths during the capital's most recent heatwaves this year, when temperatures reached a record 38C¹. London's ambulance service dealt with 25,000 more calls this summer than last, surpassing the record number set during the peak of the Covid-19 pandemic¹. London has experienced five heatwaves this summer so far¹.

Why it matters for households

The estimates cover deaths across the country in May and June, with London identified as the region with the highest proportion of heat-related deaths over the longer period¹. The ONS links vulnerability in the capital partly to living costs and household overcrowding, which it says may limit the capacity to adapt to high temperatures¹. The figures exclude the most recent heatwaves of this year¹.

The Met Office said there had been 24 days in 2026 when 30C was exceeded somewhere in the UK, matching the number of 30C-plus days in the summer of 1976². Several water companies, including Affinity Water, Anglian Water and Southern Water, announced hosepipe bans, or Temporary Use Bans, as a third heatwave swept over the UK; using a hosepipe during a ban can lead to a fine of up to £1,000, and reports of breaches go to the water company rather than the police². The London Fire Brigade issued warnings about barbecuing in open spaces amid drought conditions and about using barbecues at homes².

The Standard reported that there is not currently a legally binding maximum working temperature, and that a petition has been launched to start one². The ONS said identifying which groups are most vulnerable can help inform climate adaptation planning and public health interventions¹.

What happens next

No further UKHSA publication or timetable for revised figures has been reported. The Standard reported on 16 July 2026 that a drop in temperatures was expected over the weekend, followed by a fourth heatwave of the year the following week, with almost no rain predicted in medium-term forecasts for London².

The UK Health Security Agency publishes alerts and outbreak advice, and the site's heatwaves and drought section covers why UK summers are getting hotter and drier.