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 reported a provisional June record of 36.1C in Gosport, Hampshire, on Wednesday afternoon as a red extreme heat warning remained in force across parts of south and central England and south Wales. The UK Health Security Agency extended its red heat-health alert and transport operators cut services while emergency responses scaled up in the hottest zones.
The escalation matters because the red alert signals population-wide risk with potential for serious illness and pressure on critical infrastructure. Authorities urged residents to avoid non-essential travel and to stay hydrated as hospital cooling systems, rail power supplies and local services came under heat stress.
Last update: 25 June 2026.
Record 36.1C and extended red alerts
Gosport’s 36.1C surpassed the previous UK June highs of 35.6C in Southampton (1976) and Camden (1957), with the temperature logged between 15:00 and 16:00 BST.
Nearby locations approached the mark, including Wisley (Surrey) at 36.0C, Wiggonholt (West Sussex) at 35.9C and Charlwood (Surrey) at 35.7C. In Wales, Cardiff Bute Park reached 33.3C, its hottest day of the year to date, underscoring the breadth of the event across the south.
The Met Office maintained a red warning for parts of south and central England and south Wales complemented by amber warnings nearby. The red heat-health alert was extended until 23:00 BST on Friday. Dr. Agostinho Sousa said: “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.” Forecast guidance also warned of tropical nights when temperatures stay above 20C, hampering overnight recovery.
Transport and infrastructure under heat stress
Rail operators including South Western Railway Thameslink, Northern and Avanti West Coast reduced timetables and advised against non-essential travel as heat-related speed restrictions and equipment resilience issues mounted. Transport for London cautioned 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 were cancelled or delayed due to an electricity supply failure, compounding the wider heat-induced constraints.
Road travel also faced heavy strain. On the M25 near Godstone in Surrey, people stranded after a crash received treatment for heat-related illness as carriageway temperatures climbed. Local councils set up shaded waiting areas where feasible, while operators monitored rails, catenary systems and cooling equipment to limit failures. Schools, including The Hurst School in Berkshire, shortened days as some classrooms reached the high 30s, and public agencies continued to advise motorists to carry water and plan for delays.
Water restrictions and supply incidents
Water companies moved to conserve resources as demand surged. South East Water introduced a hosepipe ban affecting households in Kent, Surrey, Hampshire, Berkshire and Sussex after treating 644 million litres on Sunday, 56 million above the June average. Wessex Water urged customers to cut non-essential use, noting that grass tolerates hot, dry spells and that reducing hose use can save water and limit weeds.
Separate supply incidents added to local pressure. Near York a third-party pollution incident caused low water pressure for households in Easingwold and Tollerton, with bottled water stations set up while work to stabilise supplies continued. In Witney west Oxfordshire, a burst water main left some homes with low pressure or no water as Thames Water deployed repair crews. Officials encouraged residents across affected areas to follow water-saving tips and to monitor local advisories during the heatwave period.
Health impacts and emergency responses
Emergency services across southern England reported a rise in heat-related calls. A critical incident was declared at Testwood Lakes in Hampshire after a 15-year-old boy was reported missing, having last been seen swimming; marine units, NPAS, South Central Ambulance Service and the Hampshire and Isle of Wight Fire Service led search operations. In Dorset and Wiltshire fire and rescue teams noted increased 999 calls from heat-triggered smoke alarms and asked residents to check for heat as a possible cause before dialling.
Hospitals faced heat stress on key systems. Queen Alexandra Hospital in Portsmouth declared a critical incident following chiller unit failures that raised temperatures in digital systems, theatres and diagnostic facilities, while maintaining essential and emergency services. Outreach teams from St Mungo’s delivered water and sunscreen to rough sleepers in Reading; Wendy Dodds said, “If we don’t deliver water, somebody could die.” Local authorities, including Slough Borough Council, opened cool spaces with air conditioning, water and seating to support vulnerable residents.
Warnings coverage and European context
The Met Office issued a rare red warning from 9am on Wednesday to 9pm on Thursday for parts of England and Wales, including areas around London, Swansea, Somerset and Birmingham. Forecasters signalled that temperatures could climb higher in some places, with potential to approach 40C in parts of England and Wales, even as the UK’s June record moved to 36.1C in Gosport. Public advice emphasised hydration, avoiding peak sun and keeping homes cool as agencies continued to update guidance.
The UK heatwave formed part of a wider European event driving record highs, with parts of France reporting their hottest day since 1947 and readings exceeding 40C in several areas. Authorities indicated that heat would persist into the weekend for some southern and eastern English counties, with amber weather warnings complementing the red alerts in the most affected zones. Tourists and residents sought shade, fans and cooled indoor spaces as mitigation measures continued and infrastructure operators worked to sustain essential services.
