Britain is staring down a potentially historic heat surge as rare red warnings take hold, prompting school closures and blunt advice for people to stay put unless travel is essential.
Forecasters say temperatures could reach 40C today and tomorrow in parts of England and Wales, as a “heat-dome” parked over western Europe drives extreme conditions across the continent.
The UK Met Office has issued a red weather warning for extreme heat from 9am today until 9pm tomorrow, covering a wide swathe from London to Swansea and from Somerset to Birmingham.
The peak temperature of this heatwave could break the current UK record from four years ago
At the height of the heatwave over these two days, temperatures could approach the UK’s all-time record of 40.3C, recorded in Lincolnshire in July 2022.
This spell is also forecast to beat the June record of 35.6C, set in Hampshire in 1976.
The Met Office warned that a dangerous mix of intense heat and high humidity could strain public health, disrupt infrastructure, and put pressure on power and water supplies, while also creating heat-related challenges for sectors including transport, energy and water.
It also cautioned that the hot weather could lead to more water safety incidents, as larger numbers head for beaches, lakes and rivers to cool off.
Met Office spokesman Grahame Madge said: “The Met Office is flagging 39C as a headline maximum temperature on Thursday, most likely for somewhere in London or the southeast.
A commuter uses a fan in an attempt to cool down as she exits a tube carriage
“It is important to remember that the temperature value is only one element of this extreme heatwave story.
“The other major factor is the high humidity, which for many will make the intense heat even harder to endure.”
Red heat health alerts have been issued by the UK Health Security Agency (UKHSA) for the east of England, east midlands, London, the southeast, the southwest and the west midlands, with amber heat health alerts covering the northeast, northwest, and Yorkshire and the Humber.
The alerts run from 1am on Wednesday to 11pm on Thursday and indicate that “adverse temperatures are likely to impact on the health and wellbeing of the population”.
With the highest temperatures expected today and tomorrow, parents are also facing disruption as hundreds of schools close early or shut entirely to protect pupils.
Tavel advice during the extreme heat pictured at Euston station in London
Some schools have relaxed uniform rules, telling children they can wear PE kit instead of standard attire that may include long trousers and blazers.
Transport leaders, meanwhile, have urged the public to avoid travelling today and tomorrow, warning anyone who must make a journey to “prepare for a disrupted journey”.
Avanti West Coast said it planned to run fewer services than usual between Tuesday and tomorrow, adding there was “a risk of further disruption”.
Chiltern Railways said it had cut more than half of its services until Friday “to ensure the safe operation of the railway”.
Eurostar has cancelled four trains scheduled to run between London and Paris today and tomorrow “due to expected adverse weather”.
Across the Irish Sea, Met Éireann said the current run of high temperatures is expected to peak tomorrow, with the potential for Ireland’s all-time record to be broken.
A Status Yellow high temperature warning remains in place until 9am on Friday for all of Ireland.
Speaking on RTÉ’s Morning Ireland, Met Éireann’s Ailís Hankinson said sunshine would follow a cloudy start today.
“We will see temperatures today getting up to 28 degrees, but really it’s tomorrow then where we’ll see the peak of the heat,” she said.
Heatwave leaves 68,000 homes in France without power
In northwestern France, about 68,000 households have been left without electricity, authorities said, marking the first major power outage of the latest bout of extreme weather.
The outage involved a transformer on the electricity grid and was linked to extreme temperatures, with no injuries reported, the prefecture in the coastal department of Finistere said in a statement.
The problem began at around 9pm (8pm Irish time) last night in the commune of Ergue-Gaberic near Quimper in Brittany, the prefecture said.
Although teams from grid operators RTE and Enedis worked through the night, officials said full restoration is not expected until at least the end of the day.
A pharmacy displays a temperature of 48C in the village of Roussillon
By last night, as the sweltering heatwave pushed France into its hottest day ever, up to 106,000 customers of the French power network had lost power.
“For technical reasons, RTE will not be able to re-connect the affected households during the course of the day; connections will be made, at the earliest, by the end of Wednesday,” the operator said.
Finistere is among 58 French departments placed under the highest red alert for extreme heat, with temperatures of 39C to 41C forecast from Brittany to the Paris region.
Experts have said the extreme conditions are being fuelled by atmospheric and circulation patterns that trap hot air over an area for days at a time — a situation made worse by global warming.
