Motorists have been warned to take extra care on icy roads as temperatures dipped below freezing in many parts of the UK.
The mercury dipped down as low minus 6C (21F) overnight on Friday, leaving widespread frost.
Police in Wales and Scotland have been urging drivers to take extra care, with a number of accidents already reported.
Last-minute shoppers were also warned there is a risk of tumbling on icy pavements.
Forecasters said the cold snap is set to continue throughout the weekend.
A yellow severe weather warning was issued for Saturday night into Sunday morning covering Scotland, the north of England, Wales and the West Midlands.
But those hoping for a white Christmas this year could find themselves disappointed, as milder weather looks set to return through next week.
Temperatures dropped to minus 6.4C (43F) in Tyndrum, south-west Scotland, overnight, while most places saw temperatures hovering around freezing or minus 1C (30F).
Met Office forecaster Greg Dewhurst said: "We've had a bit of rain falling on frozen ground in some places, which can lead to ice forming first thing this morning.
"For those out Christmas shopping, it could be a bit of a tricky start.
"There's another cold night to come, and Sunday into Monday - perhaps even Monday into Tuesday too - but eventually we will see some milder conditions with temperatures reaching double figures."
East Anglia could remain slightly chillier than elsewhere next week, only reaching about 7C (44F), but the rest of the UK could climb to about 10C or 11C (51F).
Over the festive period, the north looks set for a wetter and windier outlook, while the south will see more settled weather, long-range forecasts show.
Mr Dewhurst added: "It's still a little bit too early to say, but generally it looks like a milder, breezy and wet theme.
"There are hints that there could be a few colder bits coming through - but nothing like what we've seen."