The UK Health Security Agency has published a warning about how cold weather can provide a risk to older and more vulnerable people.
The Met Office has said that snow and ice will affect some areas of the country this morning, while there will be a mixture of rain and in southern areas.
Here are some pictures of the arctic conditions seen across the UK.
Good morning
More sleet and snow is expected across southern England and south Wales on Wednesday while scattered snow and hail showers will affect Scotland’s northern coasts as the Arctic blast intensifies.
The Met Office’s early morning radar showed an area of rain moving in from the south and west which was starting to turn increasingly to sleet and snow as it pushed north and east.
The conditions are expected to bring more snow and ice throughout the UK, the Met Office said.
The forecasting body’s chief meteorologist, Matthew Lehnert, said the weather could cut off rural communities in the north and impact travel over the next few days across southern England and south Wales.
A number of national severe warnings for snow and ice were issued, with the Met Office saying further warnings, or updates to the current warnings, are “very likely”.
Lehnert said: “Snow, ice and low temperatures are the main themes of this week’s forecast, with the UK under an Arctic maritime air mass.
“Snow could lead to some travel disruption, with a chance some rural communities in the north could be cut off.
“The focus for the snow moves to southern England and south Wales tomorrow and some may wake up to a few centimetres of snow, with the south coast and far south-west likely to see a mix of rain and sleet. Further snow and hail showers are also expected along northern coasts, especially in northern Scotland.”