Brits are being warned of snow and ice with temperatures dipping to -5C making it colder than Iceland capital Reykjavik.
Arctic air has been moving in from the north bringing a shock return to wintry conditions after the balmy weather last week where there were highs of 20C.
The Met Office has issued a yellow warning for snow and ice in northern Scotland, which is running through Tuesday night and until 10am on Wednesday morning.
It states: “Snow and hail showers will lead to ice forming on untreated surfaces and hazardous driving conditions.”
People have been told: “Probably some icy patches on some untreated roads, pavements and cycle paths, leading to an increased likelihood of accidents and injuries.
“Some roads and railways are likely to be affected by snow, resulting in longer journey times by car, bus and train.”
A BBC weather map shows temperatures dropping as low as -5C on Wednesday morning while maps from WXCharts show a similarly cold outlook on Thursday where most of the country will be sub zero.
The cold snap makes it even colder in the UK than Reykjavik which is set to remain above zero for the coming week.
Met Office forecaster Clare Nasir said: "Warning for snow and ice across the north of Scotland through Tuesday and into Wednesday and eventually Arctic air strings right across the country.
"Let’s look at the broader picture and you can see the yellows just fade away as that weather front sinks down towards more southern areas during Wednesday.
"A warning in the north as that north/north easterly wind delivers snow showers across more northern and eastern areas through Wednesday as well as Thursday. The air generally turning a lot colder with the risk of frost."
During Wednesday it will remain chilly throughout the day.
"Frosty and icy start across Scotland, it will be cold," said Ms Nasir.
"We will see some brighter skies emerging and eventually the cloud clearing from border regions. The rain approaching Northern Ireland will sink down through much of the province in the morning. Rain also across northern counties of England, moving in across the Midlands, East Anglia and some patchy rain also for the north of Wales.”
But then behind this front there will be colder air.
Ms Nasir continued: "We could see some snow over the Pennines and certainly some snow showers moving in across the north east of England, also northern and eastern areas of Scotland where they will penetrate further inland because of the wind and that will bring also quite a significant wind chill."
UK forecast for the next 5 days
Turning colder with wintry showers after a spell of rain.
Today:
Rain and hill snow continuing south across England and Wales. Rather cloudy with some scattered showers ahead, but bright and cold to the north, with heavy sleet, hail and snow showers.
Tonight:
Clear spells in the north with wintry showers and a widespread frost. In the south, rain, sleet and hill snow continuing south-eastwards.
Thursday:
Rain, sleet and hill snow clearing southeast England during the morning. Elsewhere, feeling cold with sunshine and blustery wintry showers - these most frequent in the north and east.
Outlook for Friday to Sunday:
Cold for all with sunshine and wintry showers, these most frequent for eastern coastal areas. Rain or sleet may develop across western areas overnight into Saturday. Less cold Sunday.
