The UK could be hit by a mini heatwave next week, with temperatures reaching 26C thanks to a “subtropical swell”.
Sunny weather is expected from Tuesday onwards after a rather wet weekend.
A 600-mile “subtropical swell” sweeping in across the Atlantic will make the UK as warm as Spain.
The short summer return comes after showers hit most parts of the country this weekend.
On Sunday afternoon, clouds will make their way towards southern regions of the UK, with intermittent showers expected.
Western and northern regions of the country will see the worst of rain, with heavier spells forecast for south-west Scotland and Northern Ireland.
A Met Office forecaster said: “Sunday is looking like a day of sunshine and showers across the UK.
“Showers will continue overnight but there will be clear skies at times, with temperatures in single figures.
“It will be a fairly fresh start to Sunday morning.”
The best sunshine will be across parts of Scotland and Northern Ireland, with temperatures reaching the high teens.
The mercury is set to be around 20C in the south east of England.
On Sunday evening, showers are expected across Wales and England, but they will be fading in the north of the UK.
The forecaster added: “Next week, westerly winds will bring in warmer air, but the risk of rain across northern and western areas too.”
A Met Office spokesperson said: “It is likely to turn warm in the south east of England where temperatures will rise into the low 20Cs, perhaps mid-20Cs in one or two spots.
“At present, this is not expected to fit the criteria for a heatwave, however, as this requires temperatures of 27C or higher in the south-east for at least three consecutive days.”
Met Office forecaster Marco Petagna added: “There will be notable changes to temperatures after mid-teens highs, with Azores high pressure shown arriving.”
The Met Office forecast 16C highs jumping to 20C on Monday and Tuesday in the east of Scotland, with showery and cloudier conditions in the west of the UK.
The Weather Outlook forecaster Brian Gaze said the south east of the UK might experience highs of 26C next week.
The sunnier weather conditions come after August brought some of the most unsettled weather the UK has seen for some time.
The Met Office forecast from September 9 to 18 predicts the mercury will dip “a little cooler”.
The forecast reads: “A mainly settled start is expected for this period in the south of the UK with fine and dry weather.
“Although, with clearer skies and lighter winds, mist or fog may form on some nights.
“More unsettled spells of weather are expected in the north of the UK with rain and strong winds for many, with a risk of this pushing further south at times.
“Temperatures should be around average for the time of year, however it may be a little cooler than such for some.”
Bookie Coral’s betting suggests this month could be the hottest September on record in the UK ahead of next week’s heatwave.
“Summer is going to return next week and with one last heatwave, our betting suggests this month could end as the hottest September on record,” said Coral’s John Hill.
UK 5 day weather forecast
Showers in the north and west, a few heavy ones in coastal areas later. Mainly dry in the east, and turning chilly across northern Scotland as skies clear.
Showers across the northwest developing more widely across England and Wales, some heavy for a time, before easing later. Much of Scotland and Northern Ireland dry with sunny spells.
Outlook for Monday to Wednesday:
Outbreaks of rain spreading across the north and west on Monday and Tuesday, mostly dry in the southeast. Patchy rain spreading southeast on Wednesday, sunny spells developing in the north.
-- to www.mirror.co.uk