Tuesday night could be the coldest this year so far, the Met Office has warned, with fears that Arctic air could cut off some rural communities and cause power and transport chaos.
Temperatures could fall as low as -15c in some sheltered Scottish areas, with locations that have seen snowfall especially vulnerable.
Yellow warnings are in place for snow and ice in all four nations of the UK, including in the south-east, London, East Anglia, the Midlands and south Wales until 10am on Tuesday. Warnings in Scotland will remain until Wednesday, with further snow-only warnings continuing until the end of the week.
Temperatures are set to drop almost six degrees below their coldest last March, when they reached minus 9.1C in Aboyne, Aberdeenshire. The lowest ever recorded in the month of March was in 1958, when temperatures reached -22.8C.
The lowest recorded temperature this year in the UK is -10.4C in Drumnadrochit near Inverness in the Highlands in the early hours of 19 January.
Chris Almond, a deputy chief meteorologist at the Met Office, said very cold air would spread across the UK, bringing “snow even to low levels in the north and east through Monday and Tuesday, and in excess of 10cm could accumulate, most likely on high ground in the north, but also settling for a time at lower levels”.
Met Office spokesperson Grahame Madge said: “Temperatures will be much, much colder than we would expect at this time of year.
“The pattern will set in for some time. We have got this feed of cold air coming in from a much higher latitude.
“We expect these conditions to remain in place until at least next weekend and possibly longer because sometimes these conditions can be quite stubborn and not easily subject to change.”
Forecasters said there was a small chance of travel delays on roads, with some vehicles becoming stranded, along with delayed or cancelled rail and air travel, and a slight chance that some rural communities could become cut off – as well as a small chance of power outages and problems with other services such as mobile phone coverage.
National Highways said people should keep warm clothes and a torch in their car in case they get stuck in the freezing conditions.
On Monday, the UK Health Security Agency renewed its warnings about severe cold weather this week, saying there was a “90% probability” it would arrive, with icy conditions or heavy snow expected for most of the week in parts of England.
“This weather could increase the health risks to vulnerable patients and disrupt the delivery of services,” the agency said.
“Very cold weather is expected across most of England this week, with widespread frosts overnight and temperatures struggling to rise above freezing in some places during the day.
“A band of rain and hill snow will move southwards during Monday, perhaps bringing some snow to low levels for a time overnight into Tuesday for central, eastern and south-eastern England.
“To the north of this band, frequent snow showers will affect north-east England during Monday and Tuesday, with icy stretches developing.
“Another spell of rain, sleet and snow is likely for southern parts of England during Wednesday, then central and northern England are at risk of seeing periods of snow on Thursday and Friday.”
