Londoners are bracing for a surge in temperatures, with Monday on-course to be a balmy 33C.
Temperatures are expected to rise by the start of next week, but there will also be the threat of thunderstorms as the warm weather breaks down.
In the capital, the mercury could reach as high as 33C on Monday - which would make it the hottest day of the year.
Temperatures have already begun to climb from Sunday, which is expected to see highs of 29C, with forecasters warning it may be an uncomfortable night’s sleep for many.
Met Office Deputy Chief Meteorologist, Dan Holley, said: “We expect to see a relatively brief hotter and more humid spell of weather for Sunday and Monday, before these hotter conditions recede on Tuesday, allowing more unsettled conditions to return.
“This change to hotter conditions is caused, in part, by the effects of Tropical Storm Debby in North America.
“Debby is helping to strengthen the jet stream, causing it to meander over the Atlantic. This will allow hot air over France to move into the UK later this weekend, and early next week.”
The highest temperatures are expected in parts of central, east and southeast England, peaking on Monday at 33-34°C in some places on Monday.
This will be accompanied by some high nighttime temperatures and humidity, especially on Sunday night in southern and western areas.
However, other parts of the country are likely to be threatened by thunderstorms.
Mr Holley said: “Along with the rise in temperatures, there is also an increasing threat of heavy rain and thunderstorms on Sunday night and into Monday.
!This looks most likely across portions of Wales, northern England, Northern Ireland and southern and eastern Scotland.”
he hot spell will however come to an end on Tuesday, with "fresher" weather from the west of the country leading to more "changeable" conditions.
By Wednesday, temperatures will be in the low to mid 20s - average for this time of year.
During the spell of hot weather, the Met Office recommends that people keep curtains closed during the peak of the day and drink lots of water.
