Much of England will wake up to snow with up to 10cm expected to fall in some areas prompting fears of travel chaos.
The first wave of snow will hit most of the country and some eastern parts of Wales but a second heavier band will fall over central and eastern England later in the day.
The Met Office has upgraded its "cold weather action" warning to level three - one underneath a national emergency - for all of England, urging social and healthcare services to target specific actions at high-risk groups. It said: "This weather could increase the health risks to vulnerable patients and disrupt the delivery of services."
A number of yellow and amber warnings are also in place across the country to highlight the hazardous conditions and likelihood of disruption to travel services caused by the ice, snow and freezing temperatures.
The heaviest snow of up to 10cm will fall in Lincolnshire and north-east England, while central and east England will widely see up to 5cm with temperatures hovering around one degree.
Nick Prebble, a forecaster for MeteoGroup, the weather division of the Press Association, said: "Most places in England will see a good dusting of snow this morning, but a heavier fall will come later in the day for central and eastern England. There will widely be between 2cm and 5cm but up to 10cm in north-eastern England and Lincolnshire.
"Temperatures will be up to eight degrees in the west of England and Wales but hover around freezing point in the rest of the country. Any amount of snow which falls in this country causes disruption, and there could be some large amounts in local areas so it will undoubtedly cause some travel issues."
He added that light rain fall and freezing temperatures in some areas of England will bring a danger of ice. Snow which fell over the weekend in Scotland is expected to linger, with the possibility of a light fresh dusting on Monday.
Temperatures are expected to drop further to around minus eight degrees on Wednesday night with the possibility of more light snow flurries.
Leeds Bradford Airport later removed a warning over flight disruption from its website. A spokesman said no flights have been affected by the severe weather and the airport continues to monitor the situation.