The Met Office said a bank holiday heatwave could see temperatures reach 33 degrees and set a new record for the long weekend.
Chief meteorologist Steve Willington said most of the country will see “plenty of sunshine”.
“We've had a fairly wet and windy August so far, however that's going to change this weekend as we see high temperatures, sunshine and light winds return,” he said.
“By bank holiday Monday itself temperatures will rise further with around 33 Celsius possible in the South East - which would set a new record for the coming bank holiday weekend.”
The highest record temperature for the late August bank holiday is 31.5C at Heathrow Airport in 2001.
The late-summer heatwave could also break the Wales record of 27.3C set in 2013.
Last month saw the highest temperature ever recorded in the UK – 38.7C at Cambridge University Botanic Garden on July 25.
RAC spokesman Rod Dennis said those making the most of the long weekend with a roadtrip should check their vehicle before heading out.
“Tyre pressure and tread, as well as oil and coolant levels, should all be looked at and doing so can really cut the chances of breaking down,” she said.
HM Coastguard has urged people heading to the beach to avoid jumping into the water from “piers, rocks, cliffs or other structures that can lead to fatal incidents”.