A mini-heatwave could start as soon as Thursday with temperatures expected to reach 27C in some parts of the nation.
Met Office says widespread sunshine will see Thursday become the hottest day of the year so far, trumping today's sizzler with 25C recorded in Porthmadog, Gwynedd.
It'll mean Thursday will mark the start of what some describe as a mini-heatwave, particularly in Wales and the Southwest of England.
Greg Dewhurst, Met Office meteorologist, said: "Going forward, temperatures are going to be similar if not a little bit higher towards the end of the week."
But there will be a West-East split - so while it will be especially warm in Wales and the Southwest of England, eastern counties won't yet experience such balmy joys.
Mr Dewhurst continued: "This West-East split will be continuing with temperatures as well, so in western parts of the UK, temperatures will rise to around the mid 20s while the eastern side of the UK is more likely to see mid to high teens.
"Particularly on the coast it will remain quite chilly in the East and quite cloudy at times."
Temperature thresholds for an official heatwave vary across the nations of the UK and its regions. It also technically must be an extended period of hot weather, according to the Met Office.
Nevertheless, 26C would surpass the 25C threshold across all of Scotland, Northern Ireland, and Wales. It would also meet the same temperature threshold in the following counties;
- Cheshire
- Cornwall
- Cumbria
- Derbyshire
- Devon
- Dorset
- Durham
- East Yorkshire
- Greater Manchester
- Herefordshire
- Lancashire
- Merseyside
- Northumberland
- North Yorkshire
- Shropshire
- Somerset
- South Yorkshire
- Staffordshire
- Tyne and Wear
The mercury must reach 28C in other counties, including Greater London, to meet the official threshold.
Cloudy weather is possible on the coast and and towards the east of England though.
"There will be lots of dry weather, with the sunnier skies always in the West and cloudier skies always in the East," Mr Dewhurst said.
Many people enjoyed sunshine across the UK today. Castlederg, Northern Ireland, saw 24.5C, Bournemouth recorded 24.2C and Glasgow hit a high of 24.1C for Scotland.
While temperatures are expected to remain stable throughout the first half of the week, the South West may become windier towards the end of the week, with a risk of showers and breezes across the South.
However warm sunshine will remain for many, with the high pressure dominating to give mainly fine and settled weather.
The warmest and sunniest conditions are likely to be in the West with cloudy mornings across the East.
