Thousands may have died in UK's exceptional May and June heatwaves
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- Imperial College London, the Met Office and the London School of Hygiene and Tropical Medicine estimated more than 2,700 people may have died from heat-related causes during the UK's exceptionally hot May and June weather.
- The June heatwave — the warmest June on record in England — saw temperatures hit 37.7C at Lingwood, Norfolk, smashing the previous June high of 35.6C set in 1957.
- May set its own UK record with 35.1C at Kew Gardens on May 26, well above the previous high of 32.8C set in 1922 and equalled in 1944.
- Researchers said human-induced climate change, which has warmed the planet by roughly 1.4C since pre-industrial times, added between 3 and 4C to the maximum temperatures recorded in both heatwaves, both caused by a stalled "heat dome" of high pressure.
- A rare red heat alert was issued for parts of England and Wales during the June heatwave, warning even healthy people of significant risk to life, as hot tropical nights offered little overnight respite.
- The 2025 prediction of 3,039 heat-related deaths turned out to be roughly double the actual toll, which the UKHSA credits to heat health alerts alongside action taken across the NHS and care system.
- Dr Clair Barnes of Imperial and fellow researchers warned that on current trajectories, heat-related deaths in parts of northern Europe could begin to rival cold-related ones within a couple of decades, depending on how fast emissions are cut.
Why it matters: The June temperature of 37.7C shattered a 68-year-old record by more than 2C, and researchers attribute 3–4C of that extreme directly to human-caused warming — meaning what was once generational is now annual-grade. Roughly 2,700 estimated deaths in two months also exposes Britain's housing stock as unprepared, and the researchers' projection that heat deaths could rival cold deaths in northern Europe within decades marks a fundamental inversion of the country's seasonal mortality burden.
