Large parts of England and Wales are facing ice warnings, as temperatures will fall into minus figures overnight following prolonged periods of rain.
Hundreds of flood warnings also remain in place alongside the chilly temperatures as waters rose in several places across England.
The mercury will drop as low as minus 6C overnight in England, with the potential for the mercury to fall to between minus 10C and minus 15C in parts of Scotland, according to Met Office forecaster Simon Partridge.
Tonight is likely to be the coldest night of the winter yet 🥶
— Met Office (@metoffice) January 30, 2021
A yellow warning for ice stretching from western Welsh coasts across to London and East Anglia came into force on 8pm on Saturday, and lasts until 11am on Sunday.
On Saturday evening, the Environment Agency had put in place 90 flood warnings across England, alongside 243 less serious flood alerts, after water levels rose across the country throughout the day.
Police in Hertfordshire reported "extensive flooding" affecting a number of properties in Long Marston on Saturday afternoon, after heavy rain fell throughout the day.
⚠️ We're currently assisting the fire service in #LongMarston this afternoon (Saturday 30 January), following extensive flooding which has affected a number of properties.Road closures have been put in place and people are being asked not to travel to the area.Thank you. pic.twitter.com/u9c9MI0XLs
— Herts Police (@HertsPolice) January 30, 2021
Pictures from Gloucestershire on Saturday morning showed a children's playground partially submerged in Tewkesbury and vehicles driving through rising floodwaters in Lower Apperley.
There were similar scenes in Henley-on-Thames in Oxfordshire, where water was seen rising on to the towpath, surrounding benches and approaching riverside homes.
The wintry weather will continue next week. After some more settled conditions, Mr Partridge said: "It gets a bit more interesting as we go into Tuesday and the middle of the week."
He predicted a "much heavier" band of rain to arrive overnight on Monday into Tuesday which will "quickly turn to snow as it bumps up against cold air", and has triggered further yellow weather warnings for snow and ice on Tuesday and Wednesday.
Northern England and parts of Wales could see snow "pretty much anywhere", with 1cm to 5cm likely at lower levels and 5cm to 10cm possible in the hills.
The highest areas could get "up to 20cm or so though the course of the day", and Mr Partridge predicted that Trans-Pennine routes in particular could have some issues on Tuesday.