Temperatures could hit 14C by the middle of the week after a period of persistent gloom.
The Met Office said people could see sunshine return as soon as Monday in some parts of the country.
It will come as a relief after an “anticyclonic gloom” brought dull skies and bitter weather to much of the country.
The weekend arrived with warnings of sleet, snow and rare freezing rain in parts of England.
Parts of the UK could continue to see snowfall throughout Sunday evening and into Monday – but then things are starting to look up.
The predicted temperatures of 14C by mid-week are well above February’s average, with 6C the usual monthly average in Scotland and 9C in southern England.
This will be a “noticeable shift” after the last fortnight, which was below average, Met Office meteorologist Jonathan Vautrey said.
Don’t expect the temperatures to break records, though. February’s highest temperature was 21.2C recorded in 2019 in Kew Gardens, Mr Vautrey added.
Read more from Sky News:
BAFTAs 2025 latest: Films stars descend on London
Jockey Michael O’Sullivan dies aged 24 after fall in race
An anticylonic gloom happens when “high pressure traps a layer of moisture near to the Earth’s surface”, Met Office spokesman Stephen Dixon explains. “That brings a prolonged period of dull and cloudy weather, but with pockets of mist and fog as well.”
Weather producer Jo Robinson says anticyclones typically result in stable, fine weather, often with sunny skies in summer.
Sometimes in autumn and winter, when the sun isn’t as strong, moisture can get trapped in the anticyclone as winds are light.
This brings a layer of cloud near the surface, along with some fog and drizzle.
The cloud can often thicken overnight too as moisture condenses.
It often leads to higher levels of pollution as aerosols also become trapped.
However, some areas could go 10 days without any sunshine, which is “near record-breaking”, Met Office meteorologist Tom Morgan said.
If Lyneham in Wiltshire remains cloudy on Sunday, it will equal the site’s February record for consecutive days without any sunshine.
More western areas are likely to see some rain during the week, while eastern areas are forecast to stay drier.
Rain and potentially snow are expected in some places, particularly around East Anglia and Lincolnshire over the weekend, and into Scotland towards the beginning of next week.
Be the first to get Breaking News
Install the Sky News app for free
Follow our channel and never miss an update
Mr Morgan said: “We’ve basically got this battleground taking place over this weekend between cold air across Scandinavia and Central Europe, which is affecting eastern parts of the UK, but towards the west is a little bit milder.
“The Atlantic is trying to shift that cold air out of the way, pushing from west to east across the UK, but it’s a very slow process and it will take until the middle of the coming week for conditions to turn much milder nationwide.”
He explained the gloom “dominating” the UK over the last two weeks has been caused by a “large anticyclone”, or high-pressure system, which has been sitting over Scandinavia, bringing cold wind from the east.
“Those cold conditions have picked up a lot of moisture across the Baltic and North seas, and those moist conditions have led to a lot of clouds,” he added.
