Hundreds of thousands of Londoners lost more than four hours of sleep a night during the June heatwave, according to a new YouGov survey conducted for Greenpeace. The study revealed that an even larger number of residents in the capital missed out on between three and four hours of sleep as temperatures soared.
Heatwave Impact on Sleep
The findings come as London experiences its third heatwave of the year, with temperatures forecast to reach 33C on Thursday and remain at least 30C until Saturday, according to the Met Office. The UK Health Security Agency has upgraded its yellow health warning for the capital, the South East, and other regions to amber from Wednesday.
YouGov interviewed more than 2,000 adults across the UK, including 187 in London. While the small sample for the capital means the results should be treated with caution, they indicate that two thirds (66%) of Londoners struggled to sleep during tropical nights when temperatures did not drop below 20C. Among those who lost sleep, 45% lost between one and two hours, 30% lost between three and four hours, and 14% lost more than four hours.
Broader Health and Economic Concerns
The survey also found that 51% of Londoners said their homes were uncomfortably or dangerously hot, and 30% reported trouble travelling due to heat-related disruption. One in five (20%) said they or someone in their household felt unwell, while 46% said their workplace was too hot and 31% said they were less productive at work.
Mel Evans, head of climate at Greenpeace UK, said: “This data exposes the brutal reality of dragging our feet on climate action in the UK. Heatwaves are no longer just a novel inconvenience, they are a creeping health, housing, and economic emergency that is costing families money they don’t have. The Government must stop big polluters from heating up our planet and make sure they pay at least some of the costs of cooling our homes, securing our national infrastructure and protecting public health.”
Water Restrictions and Public Opinion
Thames Water has urged Londoners and its other customers to stop using hosepipes to water gardens or clean cars as the South East bakes in unusually hot weather, with signs of the growing threat from global warming. Additionally, 48% of Londoners backed a levy on high-polluting companies, according to the survey.
The survey was conducted by YouGov between 30th June and 1st July 2026, with data weighted to be representative of the UK adult population.
