A triple polar vortex is on the way, bringing snowfall, heavy fog and temperatures of -10C in some parts of the country.
The Met Office defines a polar vortex as numerous circulations of wind, high up in the stratosphere, above the Earth.
Chillier weather is expected over the next few days and a yellow weather alert has been issued for the Midlands and northern England.
The alert runs from today, Thursday, January 3 until Friday, January 5. It warns of possible disruptions of public transport services.
Last night, temperatures plunged to around -11C in Aberdeen, Scotland, making this morning the coldest so far in 2019.
Bitter winds are expected to continue throughout January, and experts are predicting snowfall within the next fortnight.
Speaking to the Express, Exacta Weather forecaster James Madden said: “January is looking like a colder than average month overall, and we could see some of the lowest temperatures of winter so far during the next three weeks or so.
“There is also going to be a risk of widespread snowfall through the month, this is something we are keeping our eyes on.
“While February may be slightly less cold temperatures are expected to remain largely below-average and there will be an ongoing risk of snowfall through the run-up to spring.
“There is a likelihood of seeing some significant snow events during this period, some parts of the country could see above-average snowfall for the time of year.”
The Met Office is warning of frost and 'freezing fog' on Thursday across England, Wales and eastern Scotland.
Otherwise known as ice fog, it occurs when droplets of water freeze. It only happens when temperatures are at or below freezing.
The patches of fog will clear up by Friday but temperatures are still expected to remain cold, and there will be cloudier skies and some rain on western upslopes.
There will be sunny spells this weekend and light winds, with fog and frost expected overnight. In northern England there will be some patches of rain expected to last until Monday, January 7.