Temperatures will lift into double figures over the next couple of days as balmy breezes blow in from the south.
It will be a stark contrast to the start of the week which saw the mercury nudge -5C (23F) in parts bringing snow to high ground.
Southern regions will hit 13C (55.4F) on Wednesday and Thursday with the north scraping double figures.
However experts warn it is a calm before the winter storm with bitter Polar winds set to sweep the nation again on Friday.
Britain’s weather will be dictated by a growing distortion in the atmospherics
John Hammond, forecaster for digital weather service weathertrending
Wintry showers are forecast in Scotland and the north with even the chance of the south seeing the first flurry of the season.
The next cold snap could hold out for much longer with bitter conditions possible into the start of December, forecasters warn.
Much of this week will be cloudy and milder than of late before the cold returns just before the weekend, according to the Met Office.
Forecaster Helen Chivers said: “It ill be chilly in the north over the next few days while across the south it will be cloudy and milder.
GETTYBitter Polar winds are set to sweep the UK on Friday
“We could see 12C (53.6F) or 13C (55.4F) on Wednesday and Thursday in any brightness with 10C (50F) possible in northern regions.
“It will start to turn colder again in Scotland from Thursday before Polar Maritime air moves across the country through the end of the week.
“There are signs that we could possibly end up with a slightly longer and colder spell of weather but this depends on a low-pressure system moving past the UK on Sunday, we have to see the track it takes and how it affects the cold air over Britain.”
Chances are increasing for the odd wintry shower to fall across high ground in the south at the start of next week, she added.
It will start to turn colder again in Scotland from Thursday, a Met Office forecaster said
She said: “There remains a small chance of some persistent rain and perhaps hill snow across some southern and southwestern parts early next week.
“Again it will depend on this low-pressure system and how it behaves.
“Thereafter, we are likely to see a blocked pattern becoming established, with a greater chance of drier, colder and brighter weather for most.”
James Madden, forecaster for Exacta Weather, said the Britain is wrapping up for a lengthy spell of cold weather.
The cold will be more severe and prolonged than we have seen so far this autumn, experts warn
Snow, which has so far been confined to the Scottish mountains and hills of the north could fall further south, he added.
He said: “After the brief mild spell we return to a colder pattern and this is likely to take us into the start of winter.
“However the cold will be more severe and prolonged cold than we have seen so far this autumn.
“There will also be an increased risk for some large low pressure systems hitting our shores raising the risk of significant and widespread snow as they clash with the colder air.”
ANDREW WILSON/EDINBURGH ELITE MEDIA
Snow has already hit Scotland
John Hammond, forecaster for digital weather service weathertrending, warned Britain is about to be plunged back into the freezer.
He blamed Negative Arctic Oscillation – a change in atmospheric pressure over the North Pole – for the early cold onset.
He said: “We’re starting to see a Negative Arctic Oscillation – a reorganisation of energy patterns that could block warm westerly winds and open the door to icy blasts of Arctic air.
“It’s safe to say that by [the] weekend, the freezer door will be well and truly ajar.
“Britain’s weather will be dictated by a growing distortion in the atmospherics.”