Lead Weather Presenter
PA MediaTemperatures are expected to reach above 30C for a second day running, as an early summer heatwave grips the UK.
Hot and dry conditions are expected to persist across the country, with temperatures potentially going as high as 32C in central England.
Friday is not forecast to be as warm as Thursday - which was the hottest day of the year so far - while temperatures could top out at 34C on Saturday.
The UK Health Security Agency (UKHSA) has issued an amber heat-health alert for all regions in England - the first time since September 2023 - which will remain in place until Monday.
It warns "significant impacts are likely" across health and social care services, including a rise in deaths, particularly among those aged 65 and over or people with health conditions.
By Friday afternoon, many regions are expected to meet the criteria for a heatwave - which means a temperature threshold is sustained for three consecutive days - according to the Met Office.
The threshold varies across different regions, from 25C in northern and western parts of the UK to 28C in south-eastern England.
A heatwave may be declared in London on Friday, where it has passed the 28C threshold for two days in a row.
On Thursday, Suffolk became the first area in the UK to officially enter a heatwave, after temperatures surpassed 27C for a third consecutive day.
Scotland is forecast to reach 28C on Friday, while Northern Ireland may see highs in excess of 25C. For England and Wales, maximum temperatures will range from 28C to 31C.
The heatwave is expected to peak on Saturday, with thundery showers forecast for northern Wales and north-west England, as well as dry and hot conditions in the east.
Some relief is anticipated on Sunday, when the south and east of England will dip to the high 20s, while temperatures will cool to the mid-20s elsewhere.
Despite the heat being record-breaking for 2025, temperatures are still below the June peak of 35.6C in 1976.
A developing area of high pressure is helping draw hot weather in from other parts of Western Europe. France and Spain could see temperatures close to 40C over the coming days.
Firefighters have also responded to more than 500 wildfires across England and Wales this year - a 717% surge on the same period in 2024, the National Fire Chiefs Council said.
NFCC Chair Phil Garrigan said the organisation was "deeply concerned about the escalating threat of wildfires this summer", which he warned have "the potential to become more frequent, intense and dangerous".
The organisation is urging the public to be careful when lighting barbecues and handling objects, such as glass bottles, that can cause a fire outside.
While linking climate change with specific individual extreme weather events can be difficult, scientists say that climate change is generally making heatwaves hotter and longer.
The World Weather Attribution group says that the chance of reaching 32C in June has increased by 100 times since the pre-industrial era.
Temperatures are expected to peak on Saturday
Meanwhile, the chance of a three-day June heatwave had increased tenfold due to human-induced climate change, going from a one-in-50-year event to a one-in-five-year event.
Ben Clarke, a researcher at the Centre for Environmental Policy at Imperial College London, said that with "every fraction of a degree of warming, the UK will experience hotter, more dangerous heatwaves".
He added: "This means more heat deaths, more pressure on the NHS, more transport disruptions, tougher work conditions and poorer air quality."
Dr Agostinho Sousa, head of extreme events and health protection at UKHSA described heat as the "silent killer".
"It will impact all of us, even people who consider themselves healthy," he told BBC Breakfast.
He advised people to look out for vulnerable individuals on public transport and to keep an eye on elderly people.
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