Temperatures will plunge below freezing on December 25 but no sign of snow yet 

Britain is set for a chilly Christmas, with temperatures plunging below freezing on December 25 – but no sign of snow just yet. 

The sub-zero temperatures are expected in parts of north-west England and cities including London, but a lack of moisture in the air is likely to prevent any snow from falling. 

Temperatures are expected to remain mild for the rest of this week before plummeting as we move closer to Christmas.  

Weather forecaster Simon King told BBC Five Live: ‘We are going to see mild weather over the next week or so and then just in time for Christmas temperatures are going to drop down, so it will turn colder over the Christmas period.

‘Temperatures will come below the average. It means for the whole White Christmas thing there will be wintery showers, and while it’s still very uncertain, it will certainly be cold enough over the Christmas period for there to be wintery precipitation. There may be snow for some, but for now though it’s really mild. 

Tomorrow, sunny spells and light showers in northern and western areas of the UK will be displaced by heavier rain moving in from the west on Friday, forecasters have said.

A yellow weather warning for rain is in place for Cornwall, Devon and South Wales, where flooding is likely and disruption to transport services and power supplies is expected, from midnight on Friday until 3am on Saturday. 

Met Office forecaster Alex Deakin said the outlook leading to Christmas was ‘uncertain’ due to confusing pressure patterns appearing in computer-generated forecasts. 

He said: ‘If you’re dreaming of a bit of snow, then there’s some good news, it does look as if it’s turning colder over the Christmas period. But of course you’ll need some moisture as well as cold for any snow. 

‘It will be turning cold over Christmas, and where there are showers they will be wintery. But details of the exact pressure pattern is too early to say at this stage.’ 

Rewinding back to early next week, Mr Deakin said low pressure causing blizzards in the US is likely to reach the UK as ‘further rain’ with ‘strong signals it will grow colder’. 

He said: ‘The main feature this weekend will be this area of low pressure, (and) showers will spiral around that.’

Around 20 to 30mm of rain is expected in western regions, with up to 60mm in hilly areas.

Temperatures are set to drop from a countrywide average of around 10C this weekend to single figures – though forecasters have said this projection is ‘very uncertain’ and subject to change by then.

The chilly temperatures in late December will be of particular interest to families planning to eat their Christmas meal outside.  

There is no law stating that you have to meet and eat with people outside, but a joint statement from the UK, Scottish and Welsh governments suggests it would help cut the spread of Covid. 

It states: ‘If you do form a Christmas bubble, then be especially careful to observe the guidance: meet outdoors where possible, wash your hands regularly, keep a distance from those you do not live with.’