Middle-aged Londoners are at the same risk of dying in a heatwave than pensioners, the London Mayor’s office is warning.
Women may also be more vulnerable than men to high temperatures.
Sir Sadiq Khan’s officials highlighted these factors to an inquiry by the London Assembly’s Planning and Regeneration Committee called: London is overheating – are our homes ready for rising temperatures?
“Most heat-related excess deaths in England are in those aged 65+ years,” the London Mayor’s Office said in written evidence to the committee amid forecasts of another period of warm weather in coming days.
“Whilst heat risk is strongly correlated with older age, there is evidence that younger adults in London have a disproportionate level of risk, with Londoners aged 45-65 years having the same risk of dying during hot weather as those aged 65+ years.”
It added: “There is some evidence that female sex is independently associated with increased risk of death on hot days.”
The City Hall officials did not explain the reasons behind middle-aged Londoners being vulnerable to heatwaves but they laid out the two forms of heat risk, each with different mechanisms, affecting different populations and routes for interventions.
* Classic heat stroke is by far the most common cause of heat-related premature mortality and ill-health, they said. Classic heat stroke is where the body is unable to regulate the response to heat, even without significant physical activity, and is primarily associated with older age and existing physical and mental health conditions.
* Exertional heat risk occurs when internal heat production from physical activity overwhelms the body’s cooling capacity, particularly in hot or humid conditions. It can occur even in younger, otherwise healthy people.
London suffers from the “urban heat island effect” where temperatures are significantly higher in the capital, due to its built-up surroundings, than areas just outside it.
Many people also commute to work including on the Tube where temperatures can soar in a heatwave.
👀In London's heatwave last week, @cityoflondon took the temperature - same day & time - in 2 nearby public squares.
— Will Norman (@willnorman) June 4, 2026
The difference is green infrastructure. Urban tree canopy & vegetation are vital for coping with the climate crisis.
That's why we're planting 🌳🌳 across LDN pic.twitter.com/oWI7tleQBG
The capital’s Cycling and Walking Commissioner Will Norman has highlighted how a green square with trees in the capital can be 4C cooler in a heatwave than a square with just concrete and buildings.
There have also been warnings of wildfires spreading to central London due to climate change.
Forecasters are predicting a period of hot weather for London just around the corner.
According to BBC Weather, the capital will bask in highs of up to 27C from Saturday, June 13 to Wednesday, June 17.
The planning and regeneration committee stressed that studies suggest that nearly 92 per cent of existing homes could be at risk of overheating by 2050 without proper adaptation.
It will hear evidence from experts on how well London’s homes are prepared for rising temperatures and more extreme heat events.
“Overheating is fundamentally a social justice issue, with the impacts felt disproportionately by those most vulnerable to heat risk, including older and younger people and those with pre-existing health conditions, as well as low-income households,” said Mete Coban, Deputy Mayor of London for Environment and Energy, and Jules Pipe, Deputy Mayor, Planning, Regeneration and the Fire Service in a letter to the committee.
“The scale of impacts is also determined by where Londoners live, with those living in high-density or high-rise flats with limited ventilation at greatest risk.
“This is evident specifically in boroughs such as Islington, Hackney, and Tower Hamlets.”
Committee members will explore how overheating affects Londoners, why some homes are more vulnerable than others, and if current planning rules and building standards are keeping pace with the climate crisis.
They will also examine the balance between passive cooling measures, such as shading and ventilation, and the increasing use of active cooling like air conditioning.
The Committee is also seeking first-hand accounts of how heatwaves are affecting Londoners, with a particular focus on how residents coped during the recent heatwave in May.
Members of the public are invited to submit their views by 5 July: https://survey.alchemer.eu/s3/91125826/London-May-Heatwave
