Almost an entire month's worth of rain is set to fall in less than one day in parts of the UK, bringing new flood warnings and ruining holiday plans for stay-cationers.
Weather forecasters say the worst-hit areas in the next 48 hours will include the south west of England and southern Scotland, where flood alerts have been issued for 30mm of rain to fall - half the average for the whole of July.
And by Friday and Saturday, heavier rain will appear: parts of the country including the north of England, Wales and parts of the East Midlands will see periods of very heavy rain.
"We are expecting intense spells of rainfall on Friday and Saturday, with between 20-40mm and maybe in excess of 60mm in a few localised areas," Met Office spokesman Charlie Powell told AOL Travel.
The average rainfall for the whole of July in the UK 69.6mm.
There are severe weather warnings in place for holiday hotspots including Devon and Cornwall, Somerset and Dorset. Campsites and holiday parks, which have already been affected by the wettest June on record, are bracing themselves for more flooding.
So when will there be some proper sunshine?
"There's no great change for the moment," said Charlie Powell. "It's going to be much the same for the next two weeks, with some dry weather and some days with showers," said the spokesman.
But as for the Olympics, there may be a silver lining to the heavy clouds. "There are always uncertainties when forecasting so far ahead, but there are certainly signs of some more settled weather towards the end of July."
The Met Office has already confirmed that the UK had the wettest June in more than a century. Provisional figures show that the double the average amount of rain fell, and it was the second record breaking month of rainfall this year.
"The total UK rainfall was 145.3mm, which is exactly twice as much as you would normally expect," said a Met Office spokesman.
It was also the second dullest June on record, with just 119.2 hours of sunshine, narrowly missing out on the record of 115.4 hours set in 1987. It has also been the coolest June since 1991, with an average temperature of just 12.3C.
Need something to cheer you up? How about some beautiful sun-drenched beaches? Check out our gallery and start plotting your escape.
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