Rush-hour motorists have been warned of the first widespread fog of the season a day before the bank holiday heatwave.
The Met office has issued a warning for those travelling early on Friday morning in southern England as dense patches of fog will affect a number of areas including Plymouth and Oxfordshire.
Friday is expected to see five million drivers embarking on journeys for a holiday or day-trip battle for road space with commuters, but the roads are expected to be busiest after 11am, when the fog should have gone.
Met Office forecaster Sophie Yeomans said: "Temperatures are expected to be between 7C (44.6F) to 15C (59F) throughout Thursday evening and Friday morning with the south of England being the most affected.
But she added the fog is expected to disappear between the hours of 7am to 8am, making way for clearer skies and sunshine across the UK.
From Friday afternoon, south-easterly winds will draw warm air from Europe towards the UK, bringing rising temperatures along with dry and settled weather.
Temperatures will rise to 26C (78.8F) in London and 24C (75.2F) in Cardiff, and the rest of the UK will be largely dry with lots of sunshine, according to the Met Office.
In Scotland, however there will be a series of showers with the north-west being the most affected area.
Ms Yeomans said: "For the rest of Scotland it's probably going to be quite cloudy most of the day but the southeast will be a bit better."
And by Monday, temperatures may reach 33C (91.4F) in southern England - which would set a new record for the late bank holiday weekend.
The highest record temperature for the late August bank holiday weekend is 31.5C (88.7F) at Heathrow Airport in 2001.
And the sunny spell could set a swathe of new records around the country, with the current hottest late summer bank holiday in Wales standing at 27.3C (81.1F) at Velindre, Powys, in 2013.
The Northern Ireland record is 27C (80.6F) recorded in Knockaraven, Co Fermanagh in 2003. Monday is not a bank holiday in Scotland.
