UK climate heat health risks May and June 2026

Authors: Dr Clair Barnes, Dr Ben Clarke, Dr Claire Bergin, Dr Mark McCarthy, Dr Fraser Lott, Dr Mariam Zachariah, Dr Theodore Keeping, Dr Garyfallos Konstantinoudis, Archie Rayner, Dr Malcolm Mistry, Prof Antonio Gasparrini, and Professor Friederike Otto.

More than 2,700 people are thought to have died from heat-related causes during the May and June heatwaves in England and Wales. Of those, it’s estimated that 42% died as a result of the extra heat caused by human-induced warming.

Researchers from Imperial College London, the Met Office and the London School of Hygiene & Tropical Medicine used historical mortality records and established peer-reviewed methods to model fatalities during both heat spikes. As Scotland and Northern Ireland were not impacted by such extreme temperatures, they focused on England and Wales.

With the UK now regularly experiencing temperatures far beyond historical norms, the findings illustrate the importance of heat adaptation to protect the most vulnerable during future heatwaves, and underline the necessity of reaching net zero emissions globally.

Key points

• Heat-related deaths: About 550 people are estimated to have died due to heat related causes during the May heatwave (21-29 May 2026) and about 2,200 during the June heatwave (18-28 June 2026) in England and Wales.
• Higher temperatures, higher risk: Approximately 59% of the deaths in May, and 38% in June are attributable to the additional heat added by human-caused climate change. Across both events, that amounts to about 42% of heat-related deaths.
• Climate-fuelled heat: Daytime maximum temperatures across England and Wales are now roughly 3-4°C hotter than they would have been without human-induced climate change, raising the health risks associated with these heatwaves. Without this extra warming, temperatures of this severity would have been far less likely to occur.
• Risk shifting north: While southern England saw the highest temperatures, estimates suggest the death rate (per million population) was similar in the Midlands. With this region less frequently exposed to extreme heat, it suggests residents there are more vulnerable to the impacts.