The heatwave is set to continue for some parts of the UK after the record-breaking bank holiday weather.
A high of 33.2C (91.6F) at Heathrow Airport made it the hottest August Bank Holiday Monday on record.
Southern and eastern parts of the UK are expected to see a fourth day of temperatures in the early 30s.
Met Office meteorologist Craig Snell told the PA news agency: “The heatwave is going to continue for some of us for another day with temperatures reaching around 33C, but also across the UK we are also starting to see a transition with some places seeing cloud and fresher air.
“This cloud will start to move up across Devon and Cornwall and through this evening it will come across northern and central parts of the UK.”
Tuesday is expected to remain largely dry with scattered showers gradually moving eastward from the South West coast and through the Midlands.
The Met Office said the risk of heavy rain and thunderstorms will increase as the week goes on.
“Temperatures will be staying close to the high 20s but the rain and thunderstorms will start moving eastward,” Mr Snell continued.
The cloud and risk of thunderstorms will then draw up across Northern Ireland and will bring cloud to more parts of the country.
Mr Snell added: “For some of us we have still got some hot weather to come but that transition over the next 48 hours will come with a risk of heavy rain and thunderstorms.”
During Monday’s record-breaking temperatures, Bala in Snowdonia National Park was the warmest place in Wales, with a top temperature of 25.5C (77.9F).
Fyvie Castle in Aberdeenshire, Scotland, reached 25C (77F) and Helen’s Bay in Northern Ireland saw the mercury rise to 21.9C (71.42F).
The previous best August Bank Holiday temperatures before this weekend were 31.5C (88.7F) at Heathrow in 2001, 27.3C in Velindre, Powys, in Wales, and 27C (80.6F) in Knockareven, Co Fermanagh, both in 2003, and 26.7C (80.06F) in Aviemore, Scotland, in 1984.