ONS estimates linked about 40,063 deaths in England and 2,070 in Wales to the hottest days from 1988 to 2025

ONS modeled 38 years of temperature and mortality data and found higher risk on the hottest and coldest 2.5 percent of days, with people aged 65 and over more vulnerable. These are modeled estimates rather than individual attributions, pointing cities toward long-term heat, housing and health planning.