The late sunshine – caused by warm air being dragged up over the UK from France – comes at the end of what has been a wet and chilly month so far.
Temperatures are set to reach 32 in the southeast of England on Sunday before they are expected to rise even further by Monday, possibly reaching a late August bank holiday record high of 33C – most likely in the southeast of England.
People attending Notting Hill Carnival on Sunday and Monday – expected to number one million – have been advised to stay hydrated amid temperatures which are forecast to surpass 30C on both days.
Anyone travelling over the weekend has been advised to pack enough food and water, and plan enough breaks for the journey.
A Met Office forecaster told The Independent: “Primarily we advise you enjoy the sun but in a safe way so exercise a bit of common sense. If you’re outside drink lots of water, wear a hat, loose linen clothing and don’t stay in the sun for too long particularly in the middle of the day to avoid burning as the UV is high at this time of year.
“Generally the advice is to avoid being outside during the hottest part of the day. We also recommend you close windows and put blinds down during the day and open the windows during night.”
The start of next week will also be hot, with temperatures reaching as high as 33C or 34C before cooling off as the week goes on. It will also become more unsettled, with a high chance of showers.
On Saturday, Gogerddan, near Aberystwyth, recorded 27.4C – a new record for the highest late August holiday weekend temperature in Wales.
The mercury rose to 30.7C at Heathrow, west London, just shy of the record of 31.5C set in the same location in 2001.
Aberdeenshire in Scotland could see 29C on Sunday, while Northern Ireland is likely to enjoy 24C.
Saturday’s high in Wales beat the previous record of 27.3C (81.1F) at Velindre, Powys, in 2013.
The Northern Ireland record stands at 27C (80.6F) recorded in Knockaraven, Co Fermanagh, in 2003.
Additional reporting by Press Association