Britain has basked in glorious sunshine but is facing winds of up to 60mph and driving rain today, according to forecasters.
The Met Office has issued a yellow weather warning for many parts of the country, while the Highways Agency has put an amber warning in place.
Affected areas include Wales, the South West, South East, London and the Midlands.
Forecasters say the winds are caused by an "unusually" deep area of low pressure, which is moving west from Northern Ireland.
Coastal and exposed areas could see gusts of up to 60mph, with winds reaching between 40mph and 55mph inland.
Motorists have been urged to take care in cross-winds on the roads. Branches and trees could also be brought down by the weather.
Claire Austin, a forecaster with MeteoGroup, the weather division of the Press Association, said the worst of the wind and rain would be experienced throughout today.
She said: "The strongest of the winds are going to be from late morning to this afternoon.
"We could see gusts of up to 50mph and over in inland Wales and the South West. If you go further to coastal and exposed places such as the South Coast gusts could reach up to 60mph.
"We have a band of rain coming through and we have gusty winds coming through. It looks as though the heaviest of the rain should be coming at about 3pm.
"The rain will come through quite quickly. It might be intense rain with downpours for a time. It is not very long lived. It will probably come down quite heavy with showers when it clears this evening."
A yellow weather warning has been issued by the Met Office until 9pm this evening, when it is expected that the winds and rain will have calmed.
The warning originally covered Wales, South West England and the South Coast but has now been extended to parts of Eastern England, covering Hertfordshire to East Anglia.
Mark Seltzer, a forecaster with the Met Office, said: "All the winds are caused by a deep area of low pressure coming in from the west.
"It is unusually deep for this time of year. Normally we don't see this sorts of winds often at this time of year. It is arriving moving slowly westwards, it is currently centred over Northern Ireland.
"It is going to slowly edge over the UK. The winds are picking up over south-west Cornwall as we speak. The winds will strengthen throughout the course of the day throughout most of the South of England.
"The strongest gusts will be around the coastal areas and hills of the South West and South West Wales. Later they will move across the South Coast towards Kent at the end of the day.
"Our main focus is the risk of disruption to transport, due to cross winds on roads. We suspect there will be a lot of people on the roads coming back from the Bank Holiday in caravans and cars. Our advice to motorists would be to slow down."
Mr Seltzer said the winds could pull down branches and trees and would be accompanied by "driving rain".
He added: "The winds will still be brisk in the evening and overnight but they will be at their strongest during daylight hours."
The Highways Agency has issued an amber alert for high-sided vehicles, caravans and motorbikes due to the strong winds between 12pm and 5pm.
In a statement, the agency said there was an "increased risk of vehicles being blown over".
"The Highways Agency, which is responsible for motorways and other major trunk roads in England, is working closely with the Met Office to monitor weather conditions and maintain safe roads and reliable journeys," it said.
"Drivers are advised to plan for their journey before they set out, checking the forecast and road conditions, to leave extra time if travel conditions are poor and to delay their journey if the weather becomes severe."