Met Office forecasters have upgraded weather warnings this weekend to amber, ahead of expected icy conditions and freezing rain.
Blizzards, heavy snow and other wintry showers will hit large parts of Scotland and northern England between 9am on Saturday and 9am on Sunday, bringing “treacherous” conditions for drivers and shoppers on one of the busiest weekends before Christmas.
A yellow weather warning already in place for ice and snow was raised on Thursday and was extended on Friday across parts of Northern Ireland and south western areas of the UK.
A spell of very windy weather is expected over the Northern Isles and parts of Caithness, Scotland, on Saturday afternoon and overnight into Sunday.
A spokeswoman for the Met Office said: “At the moment it looks like in the days leading up to Christmas it’s likely to be unsettled, with Atlantic weather systems affecting the country, bringing rain and strong winds.
“There will be quite severe weather [on Saturday].
“It could have some impact on people’s plans this weekend. Freezing rain is not that common in this country, so that could bring quite treacherous driving conditions.”
Despite bookmakers shortening their odds on a white Christmas, the Met Office says it is still too early to tell, as they only predict forecasts a maximum of seven days in advance.
The last widespread white Christmas was in 2010, when 83% of monitoring stations reported snow on the ground – the highest ever recorded.
A white Christmas is defined as one snowflake seen falling in the 24 hours of December 25 somewhere in the UK.
The Met Office uses sites across the UK, including Buckingham Palace, Aberdeen FC and Coronation Street in Manchester, to check for snowfall.
There was also a white Christmas in 2015, with 10% of stations recording snow falling, though none reported snow lying on the ground.
Wintry conditions are more likely in January and March than in December, with snow or sleet falling an average 3.9 days in December, compared to 5.3 days in January, 5.6 days in February and 4.2 days in March.
Bookmaker Ladbrokes is offering odds of 2/7 for snowfall anywhere in the UK on Christmas Day.
Alex Apati, of the bookmakers, said: “It’s looking increasingly likely we’ll see snow on Christmas Day in the UK, with the odds dropping as fast as the temperatures.”
William Hill said Aberdeen is the most likely city to have a white Christmas in 2018.
Spokesman Rupert Adams said: “The last 24 hours have been very busy as the first real chill of the winter has hit.
“The odds now suggest a real chance of a white Christmas, with the Scottish cities very much the favourites.”