Thermometers are poised to dip to -7C (19.4F) in the coming days as parts of the country experience the coldest spell of autumn so far.
The south will this time bear the brunt of the Arctic snap with cloudier skies elsewhere leading to slightly higher temperatures.
The Met Office last night issued the second cold weather health alert of the season urging elderly and vulnerable people to take extra care.
The level-2 ‘alert and readiness’ warning in place until Friday states: “There is an 80 per cent probability of severe cold weather between Monday and 3pm on Friday in parts of England.
“This weather could increase the health risks to vulnerable patients and disrupt the delivery of services.”
Overnight temperatures in England and Wales are poised to nudge -7C (19.4F) bringing the coldest night of autumn so far to the region.
Scotland and the north will be slightly milder with lows of between freezing and -5C (23F) forecast for the next couple of days.
Met Office forecaster Emma Sharples said high pressure wedged close to the UK is partly to blame for the bitter conditions.
She said: “High pressure over Scandinavia is in control at the moment keeping things calm and settled but bringing in cold air from the Continent.
“Through the week this will move southwestwards over the UK pulling Polar maritime air in from the north.
“Temperatures will drop sharply overnight with Monday night and Tuesday night both likely to bring the coldest temperatures of the season so far across England and Wales.
“Clearer skies in the south will bring slightly colder conditions to the region while more cloud cover in the north will keep it slightly milder.
“Towards the end of the week it is still going to feel cold, but there will be more cloud moving over the south reducing the risk of frosts.”
The Local Government Association (LGA) last night reassured Britons that local councils are ready for harsh winter conditions.
Spokesman Martin Tett said: “Councils are fully prepared to protect residents and minimise disruption to their residents caused by the drop in temperatures.
“They are constantly monitoring up-to-the-minute weather reports to make sure they can stay one step ahead of the weather.
“We are well prepared for the cold with 1.2 million tonnes of salt stockpiled and a fleet of state-of-the-art gritters ready to be deployed.”
The freeze comes as the Met Office warns to prepare for a very cold run up to Christmas blaming a triple-whammy of environmental factors.
Weakening winds around the Arctic Region – a so-called Polar Vortex – will allow cold air to sink southwards over the UK.
Cooling of the east Pacific – La Nina – and melting Arctic sea ice driven by warmer than usual North Atlantic waters will also drive the cold weather.
The Met Office’s latest three-month outlook warns of a “heightened risk of wintry weather” from now into January.
Adam Scaife, head of long-range prediction at the Met Office, said: “The stratosphere, tropics and Arctic sea ice are all trying to push our weather towards becoming colder over the next few weeks.
“Although it is not guaranteed, our long range predictions and those from other forecast centres suggest an increased risk of cold weather patterns early this winter.”
This year’s winter forecast is starkly different to last year when experts were warning of torrential rain and flooding.
Met Office long-range expert Jeff Knight said: “This time last year our outlook gave advance warning of the risk of the very mild, stormy and wet start to winter that was linked to the , but this year indications are very different.
“Weather patterns with more frequent northerly or easterly winds are favoured, which increases the risk of cold weather.”
The forecasts have led to a frenzy of betting on winter temperatures and snow with bookies forced to slash the odds across the board.
Coral is offering 7-4 from 2-1 that 2016 will bring the coldest winter on record with 3-1 on snow on Christmas Day in Aberdeen; 9-2 for Newcastle and 7-1 in Bristol and London.
Spokeswoman Nicola McGeady said: “The forecast has also prompted another white Christmas gamble and judging by the odds, punters’ dreams might just come true.”
Jessica Bridge of Ladbrokes which is offering 2-1 on the coldest night of the year this week, added: “Winter’s coming, and the odds are falling as quick as the temperature’s dropping, leaving punters already dreaming of a White Christmas.”
The UK’s coldest temperature so far this autumn was -12.1C (10.22F) set in Braemar, Scotland, last week, while across England and Wales it is -6.6C (20.12F).
A widespread frost is expected and a new survey of highways bosses shows that councils have stockpiled 1.2 million tonnes of salt to prepare for the months ahead.
Public Health England is calling on people to prepare for the chilly snap, warning that the “cold does kill”.
Scotland is forecast to see a low of minus 5C (23F) – but rural areas are likely to be even colder, while Northern Ireland will face temperatures of 0C (32F), with rural areas similarly expected to plummet lower.
Dr Angie Bone, from the extreme events team at Public Health England, said: “Cold does kill, even in places where the temperatures aren’t at their lowest.
“Now is the time to prepare for the cold weather forecast by the Met Office, and to think of those you know who are older, very young, or have pre-existing health conditions who are particularly vulnerable.”