There are warnings of heavy snow and blizzards this weekend with a risk of freezing rain causing travel chaos, the Met Office says.
Yellow weather warnings are in place for Scotland and northern England on Saturday and Sunday, and some rural communities are at risk of being cut off.
The Met Office also says there is a chance of injuries from slips and falls on icy surfaces, and bus and train services may be delayed or cancelled, with some road closures and longer journey times possible.
It also warned about untreated pavements and cycle paths being hazardous because of black ice.
The yellow warnings are in place between 12pm on Saturday and 10am on Sunday.
There is a risk of snow developing with strong southeasterly winds affecting northern parts of the UK on Saturday afternoon into Sunday morning.
The Met Office says the snow could be heavy at times, especially over hills.
Across northern England and southern Scotland, snow may turn to freezing rain above 200m to 300m, leading to widespread ice developing on Saturday night.
It is also likely that 2cm to 5cm of snow will fall at lower levels, while higher ground could see 10cm to 20cm.
Sky News weather producer Chris England said: "It's turning colder, with an easterly wind bringing air in from northern Europe.
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"Things look set to change at the weekend, with rain spreading across the UK and Ireland from the Atlantic.
"That will bring a spell of snow as the rain moves into the colder air later on Saturday and into Sunday."