Highs of between 31C and 33C are expected in England, particularly in the south-east, in a dramatic change from weeks of wet and windy weather that has lashed the country.
Met Office meteorologist Craig Snell said on average across the three days, its likely records will be broken.
“There’s a good chance we’ll break the record,” he told the Standard on Saturday.
— Met Office (@metoffice)August 24, 2019
“Certainly it could be, if not the warmest, then one of the warmest late summer bank holidays.”
If the mercury reaches 32C in southern England, this could surpass the 2001 late August bank holiday weekend record of 31.5C at Heathrow Airport.
On Saturday, highs are expected to reach 31C, creeping up to 32C on Sunday and potentially reaching 33C in the south-east on Monday.
With Notting Hill Carnival taking place over the Bank Holiday in west London, the one million people expected to attend the two-day event should enjoy sunshine with no trace of rain.
- — Met Office (@metoffice)August 24, 2019
Other popular events this weekend are Edinburgh Fringe Festival, Reading and Leeds Festivals, Manchester Pride, and Creamfields near Warrington in Cheshire.
The NHS has warned people to wear plenty of sun cream and drink a lot of water during the heatwave conditions.
Enjoying the heat this #bankholiday weekend? Make sure you wear plenty of sun cream, drink lots of water and of course have fun! For more tips to stay well in this hot weather, visit: https://t.co/nctnRqGVRS #heatwave #heatwaveUK pic.twitter.com/0ffoGh5I95- — NHS London (@NHSEnglandLDN)August 23, 2019
The RNLI reminded people heading to the coast to swim at lifeguarded beaches and to swim between the red and yellow flags.
In June, three people died in open water in 24 hours as temperatures soared across the UK.