During the summer of 2022, the UK experienced five distinct heatwave periods ranging from 3 to 16 days in length, which culminated in a historic national temperature record of (40.3^{\circ }\text{C}). 1, 2]
According to the UK Health Security Agency, the five heatwave episodes included:
Episode 1: 4 days (June 16 to June 19)
Episode 2: 16 days (July 10 to July 25), which included the most intense 2-day period of Level 4 extreme heat (July 18 and July 19)
Episode 3: 7 days (July 30 to August 5)
Episode 4: 10 days (August 8 to August 17)
Episode 5: 3 days (August 23 to August 25)
The UK experienced four distinct, relatively short-lived heatwaves during the summer of 2025, each lasting between 5 to 6 days. While these events were brief, they occurred throughout the season and resulted in the warmest overall UK summer on record. 1, 2, 3]
Breakdown of the 2025 heatwave events:
Heatwave 1 (Third week of June): Officially declared in mid-June, lasting about five days in central and eastern England before breaking with thunderstorms.
Heatwave 2 (Late June - Early July): This event lasted about six days for parts of Yorkshire and the Humber and five days in the East. A longer, more intense spell of this heatwave affected London and southern areas, peaking at 34.7°C between June 23 and July 2.
Heatwave 3 & 4 (July and August): Additional, intermittent heatwaves occurred during these months, pushing the overall summer average for the UK to a record-breaking 16.1°C. 1, 2, 3, 4, 5]