A rare amber warning for snow has been issued as temperatures look set to plunge to -14°C.
Weather warnings for snow and ice are in place across Scotland, much of northern England, and parts of North Wales until Thursday (January 18).
People in northern Scotland have been warned to expect the most disruption as an amber alert for snow was issued following the UK's coldest night of the winter so far.
The mercury fell to minus -14°C in Dalwhinnie in the Highlands on Tuesday night, according to provisional recordings by the Met Office, reportedly the lowest January temperature in Britain since 2019.
The Met Office has issued amber warnings for snow between 3pm on Wednesday and 6pm on Thursday in north-west Scotland and the Northern Isles, meaning road delays are likely and some vehicles could be stranded.
Hundreds of schools area again shut in Scotland on Wednesday amid the wintry weather and motorists are advised to drive with care due to "tricky" conditions.
But could other schools face closures? Here is all we know.
Why are schools closing?
School closures happen because of emergencies like severe weather. Plummeting temperatures mean it could make it unsafe for children to travel to and from schools.
The Government says schools and other education settings set their own plans and policies on how to deal with adverse-weather conditions and it is up to them individually to make "common sense" decisions based on their own risk assessments.
Schools will look at whether staffing levels can be met as well as looking at safety conditions around the school, temperatures in school buildings and more.
Are schools closing in London?
At the moment, no schools in London have closed and look unlikely to, with the worst of the weather headed for the northern parts of the UK.
Today (Wednesday January 17), all council schools and nurseries in Shetland and Orkney are shut, while 144 are closed in the Highlands and about 90 in Aberdeenshire, while others had delayed opening times.
The easiest way to check if schools are open is to look on your local authority’s website.
To find out, you can search via postcode on the Gov.UK site (for England and Wales). In Scotland, you can search for emergency school closures on the mygov.scot site.
What is next week’s weather going to be like?
The Met Office says the UK as a whole is in "the grip of a cold plunge of Arctic air" which has moved in from the north across the whole of the country.
A spokesman said: "The northerly airflow is also bringing very cold conditions for all, with snow showers for some areas at times. A number of National Severe Weather Warnings have been issued for potentially disruptive snow and ice over the coming days."
Towards the end of the week and into next week, it is predicted a "low-pressure system will move across the northern France bringing some snowfall on its northern edge".
Met Office deputy chief meteorologist Nick Silkstone said: “The track of this system still has some small but all-important uncertainties tied to its northern extent, and it has the potential to bring some snow to southern England.
"However, our preferred solution suggests minimal snowfall (a couple of centimetres at most) across parts of the extreme south of England in association with this system, but we are keeping an eye on how things develop and will update the forecast as needed.”
