Temperatures will feel as low as -7C in Devon this weekend as a the jet stream shifts bring a deep freeze to the UK.
High level weather warnings have been issued for the north of the country as a 'killer freeze' drops up to eight inches of snow in some parts.
The temperature is set to drop in the region on Thursday, with forecasters saying it will feel as cold as -2C.
By Saturday the temperature in the city, taking into account wind chill factor, will feel as cold as -7C over night.
The temperature is forecast by AccuWeather.com
The wind chill is increased by a change in wind speed and air humidity.
The Met Office says the shift is brought on by changes in the flow of the jet stream, creating a move between two types of weather.
The Uk is set to shift from a Polar Maritime to an Arctic Maritime.
The polar maritime has its origins over northern Canada and Greenland and reaches the British Isles on a north-westerly air stream.
Polar maritime is the most common air mass to affect the British Isles. This air mass starts very cold and dry but during its long passage over the relatively warm waters of the North Atlantic its temperature rises rapidly and it becomes unstable to a great depth.
This air mass is characterised by frequent showers at any time of the year. In the winter months when instability (convection) is most vigorous over the sea, hail and thunder are common across much of the western and northern side of the British Isles. However, eastern Britain may see fewer showers as here the surface heating is reduced. During the summer, the reverse is true, land temperatures are higher than sea temperatures and the heaviest showers occur over eastern England.
An arctic maritime air mass has similar characteristics to a polar maritime air mass, but because of the shorter sea track the air is colder and less moist.
Arctic air is uncommon during the summer, but when it does occur it may bring heavy showers or thunderstorms and unseasonably low temperatures.
Between October and May, the air is cold enough to produce hail showers or snow, and these are most frequent over Scotland and along the coasts exposed to northerly winds.
An arctic maritime air mass has its origins over the North Pole and the Arctic Ocean.
Polar low-pressure systems forming in this air mass can sometimes lead to widespread and heavy snowfall, but otherwise inland areas remain free of cloud in the winter months. In northern Scotland, arctic maritime is usually the coldest air mass, but over the rest of Britain, this air mass is not as cold as polar continental.
