Some parts of the UK could see a white Christmas this year, while the rest of the country will experience cold and bright weather, the Met Office has said.
The largely unsettled weather ahead of the big day will lead to colder and clearer conditions on 25 December.
Meteorologist Annie Shuttleworth said: "We could see some snow showers over the hills in northern parts of the UK - it's probably the most likely place to see any snow.
"You couldn't rule out some sleety snow further south than that, but there's a really big question mark on it."
On the week ahead, Monday will be cloudy but bright after the widespread fog on Sunday. By Tuesday, skies will clear even further, giving way to what is "likely to be the best day of the week".
The weather will be mild and unsettled on Wednesday, though.
Towards the end of the week, the Met Office said that the north and the south could see differing conditions, with areas below Wales likely to get milder temperatures while anywhere above could see colder and brighter weather.
Ms Shuttleworth said: "It's that boundary between the cold and the warm air which is where the uncertainty is, and that's where the greatest risk of seeing any snow or sleet is.
"We're expecting to see some snow in the lead-up to Christmas, but it is likely to be over high ground and if anything did fall at lower levels, we anticipate that to largely be quite sleety and to not last very long."
And if snow does fall, it'll most likely happen in the Midlands, northern England and Scotland, she added.
By Saturday, the weather could become more consistent, with Ms Shuttleworth adding: "We could see that colder weather push further south, so more areas seeing that colder, clearer weather by Christmas Day."
Cold, dry and calm weather is expected in the period between Christmas and New Year.
Odds on a white Christmas have been slashed by bookmakers for most major cities, with Coral saying Edinburgh tops the betting for where punters think snow is most likely to fall on Christmas Day.