Widespread frost is expected across much of Scotland and northern England as temperatures plummet for a second night.
The Met Office has issued yellow warnings of ice, stretching from the northern half of Scotland down to northern England up to 11am on Wednesday.
Overnight minimum temperatures are expected to drop to around minus 8C or as low as minus 10C across the highest ground in Scotland, and minus 3C in Scottish cities.
Further south temperatures will sit around freezing in built up areas - with a widespread frost.
The Met Office has warned that patches of freezing fog are expected across Lincolnshire and East Anglia, and that these will be slow to clear.
Temperatures will struggle to rise above 0C on Wednesday morning across much of the country, with the chance of some wintry showers in north-eastern areas.
But conditions into the South and South West are expected to be a little bit milder, with the mercury rising to around 4C.
Motorists are being warned to look out for icy patches on untreated roads into Wednesday with difficult driving conditions expected.
Towards the end of the week, temperatures are expected to warm up slightly as less cold air edges in, bringing rain with it.
On Monday the coldest night of the winter hit the UK after temperatures plunged in Scotland, with the Met Office recording minus 12C (10.4F) at Kinbrace in Sutherland.
In England, the temperature hit minus 8.2C (17.2F) in Benson, Oxfordshire, and even as far south as Odiham, Hampshire, minus 6.5C (20.3F) was recorded.