Temperatures are set to be well below average, with highs of just 3C (37F) in Edinburgh and Aberdeen yesterday, compared to 9C (48F) in Tomsk in Siberia and 8C (46F) in Greenland.
Temperatures in parts of Britain are expected to sink to -5C (23F) in the coming days with further icy gales and snow on the way.
Unseasonable cold weather is expected to last at least until the weekend with some forecasters predicting bitter conditions throughout next month.
Wintry storms in the capital triggered rare “thundersnow”, a combination of snowfall and intense thunder more common in winter.
Forecasts for continued severe weather prompted warnings for people with breathing conditions such as asthma to take extra care.
Andrew Proctor of Asthma UK said: “Cold air can have a severe impact on people with asthma.
“Sensitive airways can tighten up quickly, putting them at risk of a potentially life-threatening attack.
One lady in Teeside in North East shovels mounds of snow away from her car
Cold air can have a severe impact on people with asthma
Worst hit will be the North where bitter winds could make it feel close to -9C (16F) with swathes of the UK facing sleet and snow.
Flurries are possible as far south as the Midlands, Kent and the West Country. The Met Office said winds could reach 60mph in exposed regions along the east coast with the chance of snow even on lower ground.
Last night severe weather warnings issued for snow and ice across Scotland will remain in place into this morning.
Aberdeenshire was hit heavily with snow today
“There is the risk of overnight frosts and wintry showers in parts. “There is a slight change for the weekend with winds coming from the Atlantic bringing slightly milder but wetter conditions.
“But for today and tomorrow it is a similar picture to the start of the week, with cold air coming down from the north.”
Wouldn’t want to be on the open top deck in this weather in London
He said: “Later in the week, around Thursday, we may see some noticeable snow showers in parts of the country as far south as London.
Some areas across higher ground could also see developing blizzard conditions with the unsettled weather accompanied by strengthening winds.
One persistent cycler battles the blizzard in the North East
“And clearer skies in the evenings will also allow for some notable dips in temperature.”
Experts are blaming the cold weather on a change in wind direction at high-altitude.
Dr Todd Crawford, chief meteorologist for The Weather Company, said “stratospheric” conditions “may persist into May”.
He said: “Because of this, we have kept below-normal temperatures in our forecast for western Europe during the month.”