Parts of the UK have had the coldest night of the year so far, with temperatures dropping to nearly -10 ° C in places.
Rural Scotland has given birth to the cold weather with -9.9C registered in Braemar.
On Sunday evening, the temperature so far corresponded to the lowest of the fall, reaching -8.1C (17.4F) in Tulloch Bridge and Dalwhinnie.
In Northern Ireland, they dropped to -5.1C (22.8F) in Katesbridge, County Down.
Public Health England (PHE) has issued a cold weather warning until 12 noon on Wednesday.
PHE encourages people to watch out for anyone who may need help to stay warm.
Dr. Emer O'Connell said: "Older people and those with heart and lung problems are at risk of getting sick in cold weather."
The Met Office has issued a yellow warning for fog until 11am on Tuesday and says there is a risk of delays in flights or cancellations and bus and train services can also interfere.
Sky News weather presenter Stephanie Gaulter said: "The winds have been getting cold air from the north in recent days, which gives us a very cold feeling for the weather.
"The winds are expected to fall overnight over the UK and this, combined with clear skies, will allow temperatures to drop.
"Despite the icy feeling, it's unlikely that it's the coldest November on the record – it was -23.3C (-9.94F) in Braemar in 1919. Now it's cold!"
But the chilly spell is not expected to last for long, with temperatures expected to rise throughout the week – though more clouds will push through the southwest from the Atlantic, increasing the risk of rain.
There is also a chance for some showers along the North Sea coast and in eastern Scotland.
Big parts of the country remains flooded, with experts warning that there may be problems Tuesday.
On Monday, the Environment Agency had issued 35 flood warnings.
On Sunday, the Severn and Avon rivers blew up their banks and left properties in Gloucestershire and Worcestershire.
And two people were rescued by helicopter after heavy thunderstorms led "big floods" in a coastal town in Cornwall.