On Friday, south-easterly winds drew warm air from Europe towards the UK, bringing rising temperatures along with dry and settled weather.
Chief meteorologist Andy Page said the weekend will be a change from the wind and rain that dogged August for the past few weeks.
“On Saturday and Sunday, there’ll be plenty of sunshine, especially in the east, with temperatures rising into the mid to high 20s Celsius for many – it’ll be warmest in south-eastern parts where 31-32C (87.8-89.6F) is likely.
“Western parts are likely to see more cloud, and a probable cooling trend through the weekend.”
With Notting Hill Carnival taking place over the bank holiday in west London, the million people expected to attend the two-day event should enjoy sunshine with no trace of rain.
Other popular events on this weekend are Edinburgh Fringe Festival, Reading and Leeds Festivals, Manchester Pride, and Creamfields, near Warrington in Cheshire.
On Monday, temperatures are likely to be lower than the weekend with the warmest weather becoming confined to the south-east, according to the Met.
Meanwhile, it will become increasingly unsettled in the north-west with rain and showers at times.
Glasgow will remain cloudy throughout the weekend with the highest temperature reaching 25C(75F) on Saturday but this will soon come to an end on Monday morning as temperatures go back down to 16C (60.8F).
If the temperature reaches 32C (89.6F) in southern England this could surpass the 2001 late August bank holiday weekend record of 31.5C (88.7F) at Heathrow Airport.
The current hottest late summer bank holiday in Wales is 27.3C (81.1F) at Velindre, Powys, in 2013, while for Northern Ireland it is 27C (80.6F) recorded in Knockaraven, Co Fermanagh in 2003.
Monday is not a bank holiday in Scotland.
People travelling over the weekend are advised by the RAC to pack enough food and water and plan enough breaks for the journey.