Britons look set to enjoy the hottest temperatures of the year for the fourth day in a row this week, with the mercury predicted to soar to 32C.
While the heatwave is forecast to continue, Thursday is likely to mark the end of steadily increasing temperatures, the Met Office said.
Highs across the UK topped 30C on Wednesday, and Wales, Scotland and Northern Ireland all enjoyed their hottest days of the year so far.
Porthmadog in north west Wales had the overall high at 31.9C.
The north west of England and western parts of Scotland could vie for that title on Thursday, with a chance thermometers could creep up even further.
A spokesman for the Met Office said: “Over the next few days the high pressure will remain so there will be blue skies across the UK and that will last certainly into the weekend.
“We may see some thunderstorms on Sunday or Monday but nothing’s certain.
“But we can expect these sorts of high temperatures to be reached certainly until Saturday.”
This is the first time in five years that temperatures have hit 30C in all four nations of the UK, the Met Office said.
“Last year for England there was a warm spell where they had five days over 30C but what makes this current spell different is that it’s nationwide,” meteorologist Bonnie Diamond said.
Easterly winds will bring temperatures down slightly but the weekend and early part of next week promises to remain sunny and warm, she said.
Diamond described a forecast earlier in the week for thunderstorms as looking “less likely”.
“It’s staying sunny and warm and dry for most (into next week),” she said.
“There is a small risk of seeing some showers developing in the far south-west but otherwise it will be dry.”
After a very dry month, there is still no rain on the horizon, particularly if the potential thunderstorms fail to materialise this weekend.
The rising temperatures have come with warnings to be careful near water and in the countryside, where fire crews have been tackling wildfires.
The Met Office’s heat-health watch alert remains at level two, meaning social and healthcare services are at the ready to reduce harm from a potential heatwave.
Public Health England has issued a warning saying the extreme heat may pose a risk to the most vulnerable.
The heat has already claimed casualties – the body of a 17-year-old boy was recovered from the River Aire in Leeds in the early hours of Wednesday morning following a search a rescue operation.
It is believed he got into difficulties while swimming on Tuesday evening.
Elsewhere, 13-year-old Ryan Evans, who went missing on Monday after getting into difficulty in Westport Lake in Stoke-on-Trent, was found dead by police.
The body of a man was also recovered from a lake in Nutfield, Surrey, on Monday.
The RNLI urged those heading to the seaside to seek out beaches with a lifeguard.
Part of Saddleworth Moor in the Peak District has been gripped by wildfire since Sunday afternoon, with the army working with fire crews battle to bring the blaze under control.
A number of homes were evacuated and pockets of fire continue to burn across an area of around six kilometres, Greater Manchester Fire and Rescue Service said.
The RSPCA also called on pet owners to keep a close eye on their animals in the heat after receiving 625 calls about animals in hot environments between June 11 and 24 – the majority about dogs in hot cars.
A spokeswoman said: “(We’re receiving) almost two calls every hour, despite the charity’s key advice being to call the police on 999 in the event of an emergency.”
Commuters have also endured delays after rail services were forced to impose speed limits due to overheating tracks.
Network Rail’s extreme weather action teams are being activated across the country to monitor “vulnerable locations”.
The operator said hot weather can cause the steel on rail lines to expand and in some cases buckle, causing travel disruption.
Slower trains exert lower forces on the track, reducing the likelihood of buckling.
South Western Railway said temperatures were expected to reach 47C on many parts of its route this week.
Services on the London Waterloo to New Malden line are being subjected to speed restrictions from 11am each day until Friday.
And while the mercury continues to rise in the UK, England’s World Cup team will also have to contend with the heat in Russia as they take on Belgium in the final group game.
The Met Office forecasts the temperature for Thursday’s game at the Kaliningrad stadium to be 22C (71.6F).