Unsettled conditions will spread across the UK for most of this weekend and into next week – just after the nation recorded its hottest ever temperature.
Severe weather warnings are in place across the country until 3pm on Sunday.
There could be cancellations to public transport, road closures, and flooding to homes and businesses.
Met Office spokesman Marco Patagna said the weekend weather will be “quite a contrast to the last few days”.
“We have a rainfall warning out until tomorrow morning for southeast Scotland,” he said.
“As you get into tomorrow most of parts of the UK are cloudy with outbreaks of rain.
“And there is another yellow rainfall warning from 9am until Sunday at 3am for Northern Ireland, south Scotland and the north and east of England.”
The UK could see 1-2 inches of rain on Saturday, with local areas expecting up to 4 inches.
He added: “But tomorrow for west Wales, and southwest England, most of the day doesn’t look too bad.
“As you get into tomorrow most of parts of the UK are cloudy with outbreaks of rain”
Met Office spokesman Marco Patagna
“There will be some sunshine in those areas.”
The Met Office added in a statement: “An area of rain is expected to move slowly and erratically northwestwards across parts of the UK on Saturday and Sunday, and while some places within the warning area may see very little others could see several hours of heavy rain.
“Accumulations of 40-60mm are possible, with perhaps as much as 80-100mm in places, especially over high ground.”
Thunderstorms are also forecast, which could be “intense” and “widespread”.
Along with the harsh conditions, industrial action could also trigger travel chaos this weekend.
East Midlands Trains (EMT) customers have been warned to expect a significantly reduced service, owing to repair work and planned strikes.
Customers have also been told to check before heading out on their journeys and not to travel on the London St Pancras-Nottingham-Sheffield route.
It comes after a record breaking week, as the mercury skyrocketed across Europe.
The UK experienced its hottest ever day on Thursday, with a reading of 38.7C recorded in Cambridge.
Sweltering conditions stranded thousands of Brits, as trains came to a standstill and roads began to melt.