Plans for bank holiday getaways could be scuppered by travel disruption as the warm weather turns to wind and rain over the weekend.
Maximum temperatures are set to plunge into the high teens by Sunday, with parts of the country expected to be battered by near gale-force winds.
Drivers are being warned to expect delays as more than 14 million cars take to the roads for trips between Thursday and Monday, according to the RAC.
Met Office meteorologist Simon Partridge said wet and windy weather could cause further trouble for those travelling over the last long weekend before the festive period.
“In places we are quite likely to see some standing water on the roads which will add to the difficult driving conditions on Sunday,” he said.
“Some areas could see winds of between 30mph to 40mph, so a wet and windy day.”
Traffic information supplier Inrix predicted that the most delayed route will be the M5 from junction four to junction one in the West Midlands between 1pm and 6pm on Friday, when journeys with a typical travel time of 21 minutes could take an extra hour.
On Saturday the M1 is predicted to be badly affected from junction 22 to junction 25 in the East Midlands, with typical journey times increasing from 16 minutes to 62 minutes.
Motorists’ frustrations with the congestion could be heightened by the knowledge that fuel prices stand at a four-year high, with Government figures showing the average cost of a litre of petrol is £1.29, while diesel is £1.33.
Engineering work on the railways means a number of routes are disrupted.
Network Rail is urging passengers not to travel on the West Coast Main Line to and from London between Saturday and Monday as London Euston is closed.
People who do travel between north-west England and the capital risk journeys that are “far longer, busier and less comfortable” than normal, the Government-owned company warned.
London Euston, the UK’s fifth busiest station, will also be closed during the following weekend, as work to replace a junction in Wembley continues.
Network Rail route managing director Martin Frobisher said: “There is never an ideal time to shut the railway but these weekends are the least disruptive times to do it.”
Engineering work will also disrupt some services to Manchester, Birmingham International and Derby.
Blustery showers in the north and west will move south-east on Friday, bringing a cool night for the UK, with some grass frost in Scotland on Saturday morning.
Sunny spells and scattered showers will follow for many, with temperatures expected to reach around 20C.
The mercury is set to dip to a maximum of between 17C and 19C on Sunday as heavy rain moves across the whole of the UK from the west.
Monday, which is a bank holiday in all the home nations except Scotland, will see conditions improve, with bright and breezy weather as well as a few scattered showers