Temperatures could soar to a balmy 29C (84F) on Wednesday – making Britain hotter than Bermuda.
On Tuesday, Brits basked in another day of sizzling hot sunshine after a roasting Bank Holiday weekend packing beaches, parks and pubs across the country.
But while some can look forward to the heatwave continuing it will grind to a humid halt for others with forecasters issuing a yellow weather warning in Western Wales and England.
In Blackpool, where temperatures soared to 25C (77F), punters got a fright when the Grand National rollercoaster broke down.
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At least 30 people, including a five-year-old boy, were forced to make the scary climb 60 feet down the ride to safety.
The wooden, twin-track ride, built in 1935, broke down at midday.
Brave staff at the Pleasure Beach climbed up the ride to get people back to the ground.
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Meanwhile, another rollercoaster at the same amusement park - the giant Big One - also stopped briefly in the heat.
Riders were able to remain seated, and it began working again minutes later.
The highest temperature recorded by the Met Office on Tuesday was 25.8C (78F) in Middle Wallop, Hampshire, making it the hottest day of 2021 so far, beating a top temperature set just the day before.
It was closely followed by 25.7C (77F) in Northolt, London.
Bank holiday Monday’s maximum temperature was 25.1C in Kinlochewe, Scotland, as sun-starved holidaymakers enjoyed the long weekend and newly restored freedoms following the lifting of many lockdown restrictions.
But the good weather will not last into Wednesday for many with forecasters issuing a yellow weather warning for thunderstorms which could pose a risk of lightning strikes and power cuts.
The warning, which is in place until 11am on Wednesday, affects large swathes of the country but particularly Western Wales and England.
The warning follows a sultry Bank Holiday weekend, where balmy temperatures hit 25C in some places.
Rain is expected to sweep into the south-west of Britain from the Bay of Biscay.
Met Office meteorologist Alex Burkill said: “The thunderstorms could bring lots of lightning, some hail, as well as some heavy rain, and with the half term there is an increased number of tourists in this area.
“The thunderstorms do then push north-eastwards into the Midlands and across more of Wales, but they also ease and break up, so these places will see some showers but they won’t be as intense.”
“The thunderstorm warning from 5am to 11am warns that there could be some short-term loss of power and other services, while delays to train services and poor road conditions are possible.”
But Mr Burkill said that Wednesday was likely to be hotter than Tuesday, with the possibility of a sizzling 28C (82F) or 29C (84F) in some areas like London and the south-east.
Wednesday is expected to start with cloud building in south-west Britain and Northern Ireland bringing scattered showers, some will be heavy and thundery.
There will be more cloud around on Thursday with outbreaks of light rain and drizzle across northern England and southern Scotland.
It should still be fine with Drier later with sunny spells in mist places and Friday will be largely dry with spells of sunshine and variable amounts of cloud cover.
The heatwave has been a welcome break for people following a washout May, which brought heavy downpours and prolonged spells of rain for much of the UK.
Wales experienced the wettest May since records began in 1862, with 245mm of rainfall, topping the previous record of 184mm set in 1967, according to the Met Office.
The UK has seen its fourth highest amount of rainfall on record for the month, with an average of 120mm.
Meanwhile, England had its fifth wettest May on record, and its wettest since 1967, with 111mm of rain.
But despite the showers in certain spots on Wednesday leading bookmaker Coral now makes this month just 6-4 to become the hottest June since records began.
The odds have been cut from 4-1 over the last week as the wet spring fades into a distant memory.
Coral’s Harry Aitkenhead said: “Summer is coming and the sun is shining down on us now.
"We have slashed the odds significantly on this June going on to become the warmest we have ever had.
“We could see a number of weather records tumble if the temperatures continue to soar as we exit spring and head into summer.”
