Record-Breaking Heatwave Hits UK with Temperatures Reaching 36.1C

The UK experienced its hottest June day on record, with temperatures reaching 36.1C in Gosport, Hampshire. Discover the widespread disruptions and health impacts caused by this extreme heatwave.

UK forecasters report a provisional UK June record of 36.1C in Gosport, Hampshire, as a red extreme heat warning remains in force and the UK Health Security Agency extends its red heat-health alert. The extreme temperatures peak on Wednesday afternoon across southern England, with disruption spreading from education and transport to hospital operations.

Last update: 25 June 2026.

The escalation matters because the red heat-health alert signals a population-wide risk with potential for serious illness and pressure on critical infrastructure. Rail operators cut services, schools shorten days, and emergency services respond to heat-related incidents while authorities urge residents to avoid non-essential travel and stay hydrated.

Record 36.1C in Gosport and red alerts extended

Gosport’s 36.1C surpasses the previous June highs of 35.6C recorded in Southampton in 1976 and Camden in 1957, with the high logged between 15:00 and 16:00 BST.

Nearby locations in southern England also approach the mark: Wisley Surrey at 36.0C, Wiggonholt West Sussex at 35.9C, and Charlwood Surrey at 35.7C. In Wales, Cardiff Bute Park records 33.3C, its hottest day of the year so far, adding to the national scope of the heat event.

The Met Office maintains a red extreme heat warning for parts of south and central England and south Wales, while the UKHSA extends the red heat-health alert until 23:00 BST on Friday. Officials warn of “population-wide adverse health effects.” Dr. Agostinho Sousa states: “A red heat health alert indicates a risk to life for even the healthy population, but simple actions like staying hydrated, avoiding the sun during the hottest part of the day, and keeping your home cool can make a big difference.”

Transport and infrastructure disruptions from Portsmouth to London

Rail operators including South Western RailwayThameslinkNorthern and Avanti West Coast reduce timetables and advise against non-essential travel. Transport for London cautions that “very high temperatures may cause disruption to some Tube and rail services.” On the south coast, trains to and from Cosham station in Portsmouth are cancelled or delayed due to an electricity supply failure, compounding heat-related speed restrictions and equipment resilience issues.

Road travel also strains under the heat. In Surrey, people stranded on the M25 near Godstone after a crash receive treatment for heat-related illness. Authorities advise motorists to carry water and plan for delays as carriageway temperatures rise. Local councils set up shaded waiting areas where feasible, while operators monitor rails, catenary systems, and cooling equipment to limit failures.

Health impacts and emergency responses in southern England

Emergency services across England respond to a surge in heat-related calls. A critical incident is declared at Testwood Lakes Hampshire, where a 15-year-old boy is reported missing after being last seen swimming; marine units, NPAS, South Central Ambulance Service, and Hampshire and Isle of Wight Fire Service lead the search. In Dorset and Wiltshire, fire and rescue teams report increased 999 calls from heat-triggered smoke alarms and ask residents to check whether heat could be the cause before dialing.

Hospitals face heat stress on key systems. Queen Alexandra Hospital in Portsmouth declares a critical incident following chiller unit failures that raise temperatures in digital systems, theatres, and diagnostic facilities, while maintaining essential and emergency services. Schools across the region, including The Hurst School in Berkshire, close early as some classrooms reach the high 30s. Outreach teams from St Mungo’s deliver water and sunscreen to rough sleepers in Reading Wendy Dodds says, “If we don’t deliver water, somebody could die.” Slough Borough Council opens cool spaces offering air conditioning, water, and seating.

European context and outlook into the weekend

The UK event sits within a wider European heatwave that drives record highs, with parts of France reporting their hottest day since 1947 and temperatures exceeding 40C in several areas. Authorities warn that heat will persist into the weekend for parts of southern and eastern England, with amber weather warnings complementing the red alerts in the most impacted zones. Tourists and residents seek shade, fans, and cooled indoor spaces as mitigation measures continue.

Forecasters and health agencies continue to monitor conditions and update guidance as temperatures remain elevated. Public advice emphasizes hydration, staying out of peak sun, and keeping homes cool while transport networks and hospitals adapt operations to sustain essential services under sustained extreme heat.