Brits in parts of the country could see a white Christmas late in the day as an Arctic blast comes in but for most areas it is set to be wet and windy.
This week has been milder after the freezing temperatures earlier in the month and it will be similar over the weekend with plenty of showers around.
But while the mercury will generally be above normal in the UK on Saturday and then the morning of Christmas Day, it will start getting colder by the afternoon and evening.
And for Boxing Day it will be a lot colder with snow building up in Scotland and there could also be flurries in northern England and Northern Ireland.
Before that it is likely to be a washout on Friday and Saturday with rain showers sweeping across the country and making driving conditions difficult at times.
Maps from WXCharts show that there could be up to 10 centimetres of snow in Scotland on Christmas Day and there could be double that on Boxing Day. There could also be more snow throughout the week for the British Isles according to the charts.
Met Office forecaster Alex Deakin said: "For most areas it is going to be a mild Christmas Day with temperatures above average and into double figures across much of the south and even into the north 8C or 9C above average for the time of year.
"But as we saw earlier, colder air is going to return as the winds start to switch direction across the north west and late in the day here we may well see some snow showers coming in making it a white Christmas here.
"Elsewhere though I think it will be a wet Christmas with mild conditions persisting at least until Christmas Day night when we start to see that colder air coming in for Boxing Day.
"So a much fresher feel to Boxing Day and there will be more snow showers then for Scotland, perhaps Northern Ireland and northern England especially on the hills and with gusty winds those snow showers likely to be blowing around and quite a bit of snow could build up through Boxing Day in western Scotland.
"Further south a bright, blustery, colder feeling with many parts of England and Wales likely to stay dry but it will be that much colder."
UK 5 day weather forecast
Today:
Foggy start for some. Early rain, heavy at times, over Wales and southern England spreads northwards reaching southern Scotland and Northern Ireland this afternoon. Brighter conditions with showers follow into the south later. Wintry showers persisting over northern Scotland. Windy.
Tonight:
Early evening rain over Northern Ireland, northern England and southern Scotland moves northwards to be mainly confined to Scotland by dawn. Some hill snow northern Scotland. Showery in the southwest.
Saturday:
Early rain and hill snow over Scotland slowly clearing from the south. Otherwise generally brighter than today but also showery in the west. Milder than of late in the north.
Outlook for Sunday to Tuesday:
Mostly unsettled and mild with rain and showers on Sunday; turning colder from the northwest later with snow showers, frequent Scotland for a time Monday. Milder and unsettled again Tuesday.
