Brits have been warned not to get caught out as temperatures plummet and the country faces a big winter freeze.
The Met Office predicts temperatures will drop below average compared to previous years over the next three months.
See also: UK weather: 120 days of snow to hit Britain
See also: 'Polar vortex 'could bring coldest winter for years to UK
After the recent balmy winters of the last few years, including the third warmest winter in 106 years, the chill in the air could take many by surprise.
Widespread snow, ice and road and rail chaos are expected after the winter's first snow hit northern England and Scotland this weekend.
A Met Office forecaster said: "Frosts look more widespread until Tuesday, with showers affecting coastal areas, giving hail, sleet and perhaps snow at times. Wednesday will be cold."
The Met Office is even briefing the Cabinet Office, emergency services, transport bosses and councils that November to January will see below average temperatures.
The cause in the icy drop is down to Polar Vortex winds.
Weathermen have predicted the high-altitude winds- which spin around the North Pole and keep cold air trapped in the Arctic- could weaken, allowing Polar air to plunge south and chill Britain.
When this happened in 2010 temperatures fell to -16C in Wales and in 2009 temperatures fell below -16C in Scotland when the Polar chill came south.
The Met Office said: "Prediction systems indicate a high chance the polar vortex will be disrupted. Such a pattern would bring cold air to the UK.'
Vulnerable people such as pensioner have been urged to take extra care in the cold weather.
National Federation of Occupational Pensioners chief executive Malcolm Booth said: "After recent mild winters, people must take care not to be caught off guard by much colder conditions predicted this winter."