Parts of the UK could see up to 5cm of snow today, with temperatures set to fall as low as -10C (14F) in some areas.
Three yellow weather warnings are currently in place, with Met Office forecasters warning that colder conditions will persist into the weekend.
The whole eastern coast of the UK, stretching from Scotland to East Anglia, is under an alert for snow and ice until 11am this morning.
Commuters are being told that journeys by road and rail could take longer than usual, and untreated icy patches could cause slips and falls.
Warnings for ice are also in force across parts of Northern Ireland and southwest England until 10am, with treacherous conditions possible as temperatures fall below freezing following showers.
The bout of wintry weather made its presence felt on Thursday, with dozens of schools in Cornwall either partially or fully closed.
Several crashes were also reported on County Durham’s roads because of snow.
A widespread frost is forecast for this morning, with overnight temperatures plunging to -6C in southwest England, -8C in Wales, and -10C in Scotland.
Temperatures are also unlikely to recover during the day, with a maximum of just 5C (41F) anticipated across the South.
The UK Health Security Agency has issued amber cold health alerts in five regions – the East Midlands, West Midlands, North West, North East and Yorkshire and the Humber – until 5 December.
It fears there could be a “significant” impact across the health and social care sector.
According to the Met Office, the UK is likely to remain in a northeasterly air flow for several days to come, meaning it will stay cold well into next week.
National Highways is urging motorists to plan their journeys, keep an eye on the weather forecast, and take extra care on the roads.
Its national network manager Dale Hipkiss said: “Freezing conditions bring so many hazards such as snow and ice, please take every possible step to understand your journey in advance and allow extra time when travelling.
“Keeping a kit of essential items like a torch and warm clothes in your vehicle can be vital.”