UK heatwaves linked to 2,700 excess deaths, study says

The UK’s intense May and June heatwaves caused about 2,700 excess deaths in England and Wales, and an analysis by Imperial College London, the Met Office and the London School of Hygiene and Tropical Medicine found 42% of those deaths were attributable to the extra heat driven by human-caused climate change.

The May heatwave was linked to about 550 heat-related deaths in nine days, while the 11 days around the June event were linked to about 2,200. The May event peaked at 35.1C at Kew Gardens in London on 26 May, after the UK’s May temperature record had already fallen the day before at the same site, when temperatures hit 34.8C.

June was hotter still. The Met Office later recorded a provisional UK maximum June temperature of 37.7C at Lingwood, Norfolk, and a provisional Wales maximum of 35.9C at Cardiff, Bute Park. June 2026 was England’s warmest June on record and the UK’s second warmest June on record, with the month split between a cool first half and an exceptionally hot second half.

Maximum daytime temperatures were about 3C to 4C hotter than they would have been in a climate not warmed by human activity. Of the estimated deaths linked to the May heatwave, around 327, or 59%, were attributable to climate change-driven extra heat. In June, around 825 deaths, or 38%, were tied to that added warming.

The UK Health Security Agency issued red heat-health alerts on 22 June for six regions of England, the West Midlands, East Midlands, South East, South West, London and the East of England, covering 24 to 25 June. UKHSA says sustained warm weather can cause serious harm, especially for older adults and people with pre-existing conditions, and advises people to check on vulnerable friends, family and neighbours, stay hydrated and keep homes cool.

The Office for National Statistics estimated 4,507 deaths in England were associated with the hottest days in 2022 alone, and 51,670 in England and 2,186 in Wales over the period from 1988 to 2022. Red extreme heat warnings are reserved for the most severe events.