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."
Weather sayings: True or false?
Weather sayings: True or false?
Seeing a ring or arc around the moon is often a good indication that the weather is changing. The Weather Channel says that due to the structure and angle of an approaching warm front a hazy layer of cloud can sometimes be seen high in the sky before the rain arrives.
Seeing a red sky at night means that an area of high pressure is moving in from the west so there will be a good chance of dry and fine weather the next day. According to The Weather Channel, red sky in the morning means that the high pressure has already passed and wet and windy weather is on its way!
True! A red sky in the morning means the high pressure system has already moved east meaning the good weather has passed and wet and windy low pressure system is heading our way.
Weather records began in 1861 and since then there has been no mention of 40 dry or 40 days of rain after St Swithin's day on 15 July, says The Weather Channel.
The Pennsylvania groundhog (Punxsutawney Phil) gives a weather prediction each year on February 5 and according to tradition, if he sees his shadow and retuns to his hole then there will be another six weeks of winter. But The Weather Channel says Phil's predictions have only been right 39 per cent of the time.
Scientists have proved that there is a link between cows' behaviour and the weather. Researchers found that cows stand when the weather is warmer and are more likely to lie on the ground when it's cooler - such as just before it rains!
Swallows fly at the same height as the insects they are trying to catch and eat. When the weather is warmer, the insects are propelled higher by the rising hot air - therefore the swallows have to fly higher when the weather is warmer!
Late night rain and early morning rain are often an indication of a front passing by and this happens as often during the day as it does as night, which means rain in the morning doesn't mean it won't rain at night.
Seagulls tend to sleep on water but when it's windy and the water becomes choppy they will move inland and huddle on the beach.
This old proverb is thought to be a warning not to take off your clout (winter clothes) until the may blossom (better known as Hawthorn) is out because it heralds warm weather. Until you see it in full bloom there's always a chance the cold weather will return in the spring months, which happens quite frequently in the UK.