England, Wales and Northern Ireland recorded their highest temperatures of 2026 on Sunday, marking the UK's hottest May day in at least 79 years. Kew Gardens in west London reached 32.3C, while Cardiff and Armagh saw 27.4C and 23.4C respectively. Scotland narrowly missed its May record, with Edinburgh hitting 23.5C, just 0.1C below the previous high.
The first area to meet the heatwave threshold was Santon Downham in Suffolk, achieving temperatures above 27C for three consecutive days by Sunday morning. Other areas officially in heatwave conditions include Heathrow, Kew Gardens, Northolt, Benson, Brooms Barn, High Beach, and Writtle. Temperatures could rise further on Monday, with possible highs of 33C to 34C.
The Met Office noted that breaking the 32.8C May record is now about three times more likely in the current climate than before the Industrial Revolution, shifting from a one-in-100-year event to a one-in-33-year event. The climate crisis is increasing the frequency and intensity of extreme heat, with similar peaks affecting large parts of western Europe.
Heatwave criteria vary by region: London and surrounding counties require 28C for three consecutive days, while other areas of England and south-east Wales have thresholds of 26C or 27C, and northern England, Scotland, Wales, and Northern Ireland use 25C. Saturday was the UK's first 30C day of the year, the earliest since 1952.
The UK Health Security Agency issued amber heat alerts for the East Midlands, West Midlands, east of England, London, and south-east, in place until Wednesday. These alerts warn of increased health risks for those over 65 or with pre-existing conditions. Authorities also urged caution around open water, as 61% of accidental water-related fatalities in 2024 occurred in inland waterways, with May having the highest number of deaths.
