Just a day before the official start to winter on December 1, the mercury is expected to fall as low as minus 10C (14F) in some parts.
Britain’s cold spell could make it cooler than Iceland’s capital Reykjavik, which is due to have a high of 7C (44.6F) later in the week, while Helsinki in Finland will see temperatures of between 3C and 4C.
The Met Office has issued ice warnings for northern parts of Scotland overnight, with snow expected to fall on higher ground.
The weather is set to get progressively colder, with Thursday and Friday likely to be the chilliest days, according to the Met Office.
Spokesman Grahame Madge said: “The weather situation is that it’s likely to be getting colder as we go towards Thursday and into Friday.
“Pretty much everywhere in the UK will be within touching distance of freezing.”
He added: “In Scotland air temperatures could drop down to minus 10C, but that’s likely only if you are out overnight in the Scottish mountains.”
In light of the temperature drop, Public Health England (PHE) warned people to look out for those most likely to be affected by the cold.
Dr Thomas Waite, of PHE’s Extreme Events team, said: “As the weather is going to get colder everywhere in the coming days, this is a really good time to check on those who may be at risk.
“People with diseases such as heart and lung conditions, older people and young children can feel the ill-effects of cold weather more than the rest of us.”
Dr Waite advised people to wear lots of thin layers instead of just one or two thick items of clothing, and to maintain a home temperature of at least 18C (64.4F).
Drivers in Scotland have been urged to be cautious amid possible icy patches on some roads due to wintry showers.
Commuters have also been told to be prepared for disruption due to cold and wet weather, with South Western Railway predicting “poor rail conditions” across the network throughout this week.
It follows a cold weekend when parts of Britain woke to an icy morning on Sunday after biting temperatures hit overnight. The mercury dipped to minus 2C in some places, while others barely managed to get above freezing.