England’s heat-associated death estimate reaches 2 877 after May and June episodes

UKHSA estimated that 753 deaths were associated with the May heat episode between May 24 and 27, with a 95% confidence interval of 529 to 977. A further 2 124 deaths were associated with the June heatwave between June 21 and 28, with a confidence interval of 1 758 to 2 491.

The combined estimate of 2 877 has a 95% confidence interval of 2 476 to 3 278. UKHSA classified the figures as interim because the calculation uses early death-registration data and remains subject to revision as further registrations become available.

The May episode averaged approximately 188 heat-associated deaths per day over four days. The eight-day June episode averaged approximately 266 per day. Mortality during both episodes reached its highest level on the hottest day of the respective period.

UKHSA calculates heat-associated mortality by comparing deaths registered during defined heat episodes with mortality during nearby non-heat periods. The estimate represents excess all-cause mortality statistically associated with hot weather and is not a count of individual death certificates identifying heat as the underlying cause.

The May and June estimate is approximately 91% higher than the 1 504 heat-associated deaths recorded during the full summer of 2025. UKHSA reported 1 311 heat-associated deaths in 2024, 2 295 in 2023 and a record 2 985 during five heat episodes in 2022.

A prolonged heat episode between July 5 and 17 is not included in the interim assessment. UKHSA said the final 2026 seasonal total is likely to be substantially higher once the July episode and any later periods of hot weather are assessed.

Finalized figures are scheduled for publication in UKHSA’s annual heat-mortality report in early 2027. The final assessment will use more complete death-registration data and may revise the estimates reported for May and June.

The May episode coincided with a new UK temperature record for the month. The Met Office verified a maximum of 35.1°C (95.2°F) at Kew Gardens, London, on May 26, surpassing the previous May record of 32.8°C (91°F), set in 1922 and equaled in 1944.

A provisional maximum of 37.7°C (99.9°F) was recorded at Lingwood, Strumpshaw Hill, Norfolk, on June 26. The temperature surpassed England’s previous June record of 35.6°C (96.1°F), recorded at Southampton in June 1976.

The June heatwave triggered a red Heat-Health Alert across six regions of England. It was only the second red alert issued under the current system, following the July 2022 heat emergency.

Red Heat-Health Alerts are reserved for conditions expected to pose a risk to life across the population, including healthy people. The effects can extend beyond health and social care to transport, water, energy supplies, food systems and businesses.

The June alert initially took effect at 01:00 LT on June 24. UKHSA later extended the highest-level alert until 23:00 LT on June 26 before conditions were downgraded.

UKHSA operates the Heat-Health Alert system in partnership with the Met Office. The system provides advance notice to health services, care providers, local authorities and emergency planners when forecast temperatures are expected to produce substantial health effects.

Early-season heat can pose particular risks because people, communities and public services have had less time to adapt to higher temperatures. UKHSA identified older adults and people with underlying medical conditions as the groups facing the greatest risk.

The June heatwave also placed additional pressure on ambulance and hospital services. London Ambulance Service received more than 53 000 emergency calls during the event and deployed 600 additional ambulance crews across the capital. Extra paramedics treated patients by telephone through the service’s clinical hub.

The ambulance service said demand during the June heatwave exceeded levels recorded at the peak of the COVID-19 pandemic. The figures describe total emergency demand during the hot-weather period and do not represent a count of incidents caused exclusively by heat.

Dr Ross Thompson, Principal Environmental Public Health Scientist at UKHSA and an author of the report, said very hot weather presents a substantial danger to health, particularly among older adults and people with underlying medical conditions.

Thompson said additional hot-weather episodes during the remainder of the summer would increase the prospect of 2026 recording the highest annual heat-associated mortality estimate in the monitoring series.

He also said periods of hot weather are expected to become longer, more frequent and more extreme as the climate warms, requiring individuals, communities and public systems to prepare for higher temperatures and protect those most vulnerable to heat.

Health and Social Care Secretary Yvette Cooper said the May and June heatwaves had affected public health and added to pressure on the National Health Service. She said health services increasingly need to prepare for severe summer heat alongside their established planning for winter pressures.

UKHSA has published an updated Adverse Weather and Health Plan for England for 2026 to 2027. The plan sets out areas in which health authorities, local government, care providers, voluntary organizations and communities can maintain and improve integrated preparedness and response arrangements.

References:

¹ Interim heat mortality monitoring report, England: May and June 2026 – UK Health Security Agency – July 30, 2026

² May 2026 temperature records verified – Met Office – June 17, 2026

³ June 2026 heatwave: A recap of the temperature records – Met Office – June 30, 2026