An estimated 1,504 people died in heat-related incidents across England during the summer of 2025, Britain’s health security authority said Thursday.

The UK Health Security Agency (UKHSA) said the deaths occurred during five periods of extreme heat that met the agency’s official thresholds for heat alerts.

The figure was lower than expected, with 1,535 fewer deaths than the 3,039 projected by modeling. The agency said several factors may have contributed to the reduction, including national and local implementation of the Adverse Weather and Health Plan and the use of heat alerts, though it is difficult to determine causality.

The 2025 total is higher than the 1,311 heat-related deaths reported in the cooler summer of 2024, but significantly lower than 2,295 in 2023 and an estimated 2,985 in 2022.

Older people remained the most affected. Those aged 85 and over recorded the highest mortality rate, at 364 deaths per million people, followed by those aged 75 to 84 at 116 per million.

Citing the assessment, Agostinho Sousa, head of Extreme Events and Health Protection at UKHSA, said the relationship between periods of hot weather and increased mortality "remains clear."

“Even as we adapt to a changing climate, older adults and those with underlying health conditions continue to face the greatest risks,” he added.

Summer 2025 was the warmest on record in the United Kingdom. (Anadolu Agency)