Temperatures are forecast to reach up to 30C in parts of the UK on Tuesday as the country enjoys a warm start to September.
The Met Office said some areas were edging close to recording an official heatwave this week as pupils head back to school.
On Monday, the maximum UK temperature was logged at 28.9C in Larkhill, Wiltshire, closely followed by the 28.8C recorded at Santon Downham, Suffolk, and 28.7C at Middle Wallop in Hampshire.
In Wales, the highest temperature was 27.1C at Usk in Monmouthshire, while the mercury reached 24C at Fyvie Castle in Scotland’s Aberdeenshire and 22.2C at Ballywatticock in Northern Ireland.
Greg Dewhurst, a Met Office meteorologist, said central and eastern England were the likely areas that could experience a maximum of 30C on Tuesday.
More widely across England and Wales, conditions will be in the mid-to-high 20s, while Scotland and Northern Ireland could see temperatures around 24C to 25C.
Mr Dewhurst said low pressure moving in from the south west on Wednesday make it “less hot” in parts of Wales and Northern Ireland, but “hot air” will remain in central and eastern England and Scotland, bringing highs of 26C to 29C.
Temperatures will fall later in the week, with an increased risk of some heavy showers.
Mr Dewhurst said central and eastern parts of England were “most likely” to record an official heatwave across Monday to Wednesday, but will only “just about make it”.
Here is a reminder of this morning's forecast ⤵️ https://t.co/A6lsiTCsMz
— Met Office (@metoffice) September 7, 2021
A location meets the UK heatwave threshold when it records a period of at least three consecutive days of daily maximum temperature levels meeting or exceeding thresholds which vary across the country.
These include 25C for Wales, Scotland and south-west England, 27C for southern and eastern England and 28C for London.
“We often get a warmer spell particularly early on in September,” Mr Dewhurst said, adding: “August was particularly cool… and cloudy, so this spell is the warmest spell of weather since July for the UK.”
September has already beaten this August’s highest temperature of 27.2C in the UK, which last happened in 2016.
The current warm weather follows the official end of summer, from a meteorological point of view, which is considered to be August 31.