Cold wind, freezing fog and snow will all move southwards. Overnight lows of 0 to 2 degrees Celsius with frost anywhere sheltered from the wind.
Northern Ireland, Scotland and northern England will be the worst hit by snow showers, which will follow a band of wet and windy weather on Sunday night and into Monday.
Yesterday we reported that a snow and ice weather warning had been issued for the majority of the counties in the North of Ireland, and today that warning has been expanded upon.
The Met Office's chief forecaster predicts: "Snow showers will be heaviest and most frequent across western Scotland".
Travel delays and the cancellation of public transport are possibilities.
The Met Office is warning that weather across the United Kingdom is about "to take quite a dramatic turn".
Untreated roads and pavements are also likely to become icy during this time, creating a skid and slip hazard.
There is also a possibility of power cuts, and other services like mobile phone coverage being impacted.
Some forecasters are warning that.
Forecaster Eleanor Bell, of The Weather Channel, said: "Currently we are forecasting colder weather next week".
"The calm misty weather of recent days will be replaced by wind, rain and eventually heavy snow for millions as the jet stream sends an express delivery of Arctic air straight from Canada".
"The northwest of the United Kingdom will bear the brunt of the heavy snow showers, with several feet of snow on the mountains by midweek".
"In northern England, Northern Ireland and Scotland there will be a greater chance of the snow lying".
In Cumbria heavy rainfall is expected tomorrow while the south of Scotland could face frequent and heavy hail and snow showers on Monday and Tuesday.
"There's no respite from the cold weather and our odds suggest that some places in the United Kingdom this weekend will again get snow", a spokesperson said.