The start of the August long weekend was accompanied by downpours and below-average temperatures across the UK.

Heavy rains were reported in central and southern regions, with up to 70mm forecast. Much of the southeast was under a yellow weather warning until Saturday afternoon.

According to the Met Office, there will be more stormy showers on Saturday night, mainly in the north and west. London will be around 15 degrees Celsius and Manchester 14 degrees Celsius.

The weather will improve on Sunday, although some showers are expected in the east, north of England and south of Scotland.

Winds will increase and much of the UK will be stormy, but not as severe as on Friday morning when Storm Lilian began, the Met Office said.

Dan Holley, the Met Office’s deputy chief meteorologist, said: “After Saturday, many southern and eastern areas will remain largely fine and dry for the remainder of the long weekend, with temperatures initially below average but recovering somewhat by Monday.

“However, it will remain cooler with cloudier conditions and occasional rain or showers in more north-westerly areas, with some heavy rain likely on Sunday in parts of Northern Ireland, south-west Scotland, north-west England and north Wales. This may also be accompanied by some fairly strong winds at times.”

The yellow code for rain was issued at the start of what could be the busiest day off on the road ever.

The RAC estimates that 19.2 million leisure journeys will be made by car this weekend, the highest number since the car company began collecting data for the summer bank holiday in 2015.

Earlier, National Rail said “severe weather” had blocked lines between Beverley and Scarborough, causing trains to be “cancelled, changed or delayed by up to 30 minutes”. A landslide between Honiton and Axminster had also blocked lines, prompting passengers to receive a message warning of possible disruption as “trains may be cancelled or changed”.

Wet weather overnight caused delays to the opening day of the Manx Grand Prix on the Isle of Man, while the third day of the Vitality County Championship cricket match between Middlesex and Northamptonshire was called off without a ball being bowled.

But the best weather is forecast for Monday. Met Office meteorologist Liam Eslick said: “There will be more sunshine and the winds are expected to ease. It will be a lot quieter with the bank holiday on Monday and it will be nice to have that extra day to enjoy this weekend.”