The Bank Holiday weather “curse” is set to strike again – with lightning and thunderstorms to dump almost a month’s rain in an hour as temperatures soar to 27C.
Forecasters say the day off work for Britons could be ruined with floods possible and lightning threatening power cuts.
The Met Office forecast thunderstorms delivering up to 40mm in an hour into tomorrow in the South and Midlands.
The North is also facing rain tomorrow.
Parts of the South averaged 50mm of rain in the whole of May.
Hail the size of pound coins hit near Newcastle on Saturday as many regions saw storms and 53mm of rain deluged Levens Hall, Cumbria.
Steamy highs will climb again from today’s 25C to 27C tomorrow, the Met Office said.
But temps will hit 22C in the capital amid forecasts of rain.
More rain is due on Tuesday as strong winds threaten the North, with drier 23C midweek highs.
The Weather Outlook forecaster Brian Gaze said: “Britain’s Bank Holiday weekend weather curse is striking again, with storms and floods after hot and dry weather during the working week.”
The Met Office said: “Sudden flooding of roads, transport routes, homes and businesses is possible locally. Lightning strikes are possible, bringing a chance of disruption to power.”
Met Office forecaster Martin Bowles said: “It does not look promising for the Bank Holiday.
“Thunderstorms mean there could be localised surface water flooding.
“Highs have been 10C above average for late May in many places. But now it will get fresher.”
The Weather Channel said: “The Bank Holiday weekend looks wet – typical.”
Traffic clogged coastal routes over the weekend including the A23 to Brighton, A31 to Dorset, A30 to Cornwall and M55 to Blackpool.
The biggest weekend beach dash since last summer saw Brighton due 250,000 weekend sunseekers, with 100,000 at Bournemouth and 80,000 at Great Yarmouth.
A BBQ rush saw Asda expected to sell 750,000 burgers and 350,000 sausages this weekend.
Tesco is set to sell 150,000 ice lollies, more than 2 million bottles of beer and 1.6 million bottles of wine.
Saturday saw 27C after Friday’s peak of 29.4C in Lossiemouth, Moray, Scotland, broke 160-year old records for the hottest ever May 26.
The record had been 29.3C, in 1880 in Norwood, south London, date temperature records used to compile Met Office records showed.
Britain was hotter than 28C Kingston, Jamaica.
But the “wrong type of heat” was blamed as Britain’s heatwave was too hot for trains – with passengers delayed as Network Rail halved some train speeds as rails risked buckling.
Network Rail said it imposed some speed restrictions – which usually halve train speeds – as “direct sunshine” threatened to buckle rails.
Hot but cloudy conditions cause fewer problems as the sunshine reaching ground level is weaker.
Dozens of services are understood to have been delayed, by up to 30 minutes.
Network Rail speed restrictions have included Virgin Trains’ west coast main line between Lancaster and Preston, and Milton Keynes and Rugby – also hitting London Midland.
Other firms suffering speed restriction delays include Great Western Railway and Arriva Trains Wales on the London-Wales main line near Cardiff, and Greater Anglia between Norwich and Lowestoft.
Stephen Ng tweeted: “I’ve heard it all now. GWR say the rails between Cardiff and Newport are too hot, hence a speed restriction and 23 minutes late.”
Network Rail said: “Rails in direct sunshine can be 20C hotter than air temperature. Rails expand as they get hotter and can start to buckle.
“Speed restrictions are imposed as slower trains exert lower forces on the track, reducing the chance of buckling.”
Heatwave deaths were feared.
Three hundred extra Brits died in July 2009 amid 32C highs, Department of Health records show.
A total of 2,139 Brits died due to August 2003’s record 38.5C heatwave.
Public Health England’s Heatwave Plan for England said: “Excessive exposure to high temperatures can kill. Excess seasonal deaths start to occur at 25C.”
National Federation of Occupational Pensioners chief executive Malcolm Booth said: “Hot weather can have a disastrous effect on the elderly, vulnerable adults and children.”