The UK is preparing itself for a big freeze.
Many parts of Britain will be braced for temperatures below zero in the run-up to Christmas, forecasters have predicted.
They say a weak polar vortex above the Arctic will move south bringing freezing weather.
The public have been urged to wrap up warm as the UK could face its coldest winter for five years.
Average minimum temperatures are predicted to fall below zero in some parts of Britain.
The polar vortex is the name for the winds circling the Arctic, but it could have an adverse effect on British weather this winter.
Professor Adam Scaife from the Met Office told The Telegraph: “There is an increased risk of cold snaps between now and Christmas.”
Parts of Britain have already seen their first winter snow, with northern England and Scotland experiencing icy conditions at the weekend.
The Met Office said there will be more widespread frost on Tuesday and cold conditions on Wednesday.
On Sunday, the temperature at Benson, Oxfordshire, dropped to -2.3C.
The first snow of the cold season fell in areas such as North Yorkshire and Cumbria.