Temperatures could drop as low as -10C in the coming days, as heavy rain brought by Storm Christoph is replaced by sub-zero conditions this weekend.
Parts of the North West of England devastated by flooding on Tuesday and Wednesday turned drier overnight on Thursday as the storm moved eastwards.
"Thankfully the areas that saw a lot of rain have certainly been a bit drier today," Met Office meteorologist Craig Snell said on Thursday.
But he warned that flood-hit areas are to turn "more wintry", with a yellow warning for ice in place across Wales, the North West of England, west coast of Scotland and large parts of Northern Ireland until 10am on Friday.
Although the rain is due to ease in places like Manchester and Cheshire, where thousands have been evacuated from their homes, there could be more flooding next week.
Environment Secretary George Eustice warned that "the danger has not passed" after chairing the government's emergency COBRA committee on Thursday.
"The water levels remain high and there is the risk of possible further flooding next week so everyone needs to remain vigilant, follow the advice and sign up for flood alerts," he said.
The River Dee in Farndon, Cheshire, still carries a "danger to life" warning with water levels expected to peak at 10m (32ft).
There are a further 148 flood warnings and 137 flood alerts in place across the whole of England.
On Thursday, more than 2,000 residents were evacuated from their flood-hit homes in Didsbury, Manchester after heavy rain and snow.
"It is vital that people who are in potentially affected areas follow the advice and get the Environment Agency flood alerts where they can," he said.
At a care home in Northwich, Cheshire, 40 elderly residents were led to safety in dinghies as the town sat largely underwater on Thursday.
Cheshire Fire and Rescue Service had already rescued 21 people from Lea Court nursing home in Warrington earlier that day.
In Bangor-on-Dee and Skewen in north Wales, residents were also instructed to leave their homes.
A man's body was pulled from the River Taff in Blackweir near Cardiff on Thursday.
The death is currently being treated as unexplained, South Wales Police said.
Elsewhere in Wales, emergency teams were called out to protect supplies of the Oxford-AstraZeneca coronavirus vaccine following flooding at Wrexham Industrial Estate.
It came after a grandfather ended up in hospital having accidentally swallowed sewage water when his house in Chester flooded on Wednesday night.
Chris Spencer and his wife Marlene, who are both 70, were rescued from their home with the help of their granddaughter Alex Roberts after dirty water began seeping in.
The 20-year-old said her grandfather swallowed the water after falling over and hurting his back.
He was rushed to the Countess of Chester Hospital where he was treated for hypothermia before being discharged on Thursday morning.
Watch: Boris Johnson warns 'more flooding to come' as severe warnings remain in place