Parts of England could shiver through temperatures well below freezing on Tuesday night while northern Scotland basks in single figures, forecasters have predicted.
Met Office spokeswoman Emma Sillitoe told the Press Association clear skies will contribute to overnight temperatures in the minus figures for areas below Manchester.
"We could see minus 6C (21F) or minus 7C (19F) around the Midlands and quite widely below freezing, so even in London we could see minus 2C (28F)," she said.
Meanwhile, cloud coverage further north will keep temperatures above freezing, with Inverness reaching 5C (41F) overnight.
Monday night saw lows similar to those predicted for Tuesday night.
South Newington in Oxfordshire was the coldest place in the UK overnight, with a temperature of minus 7.5C (18.5F), while Bala, in Gwynedd, north-west Wales, reached minus 6.2C (21F).
Both places saw their coldest nights so far this season.
The chilly conditions will continue into Wednesday morning.
Ms Sillitoe said there would be a "cold, crisp start to southern and central areas" with frost.
"People will have to scrape the windows on their cars again," she added.
The north-south divide will also continue into Wednesday.
Glasgow is expected to peak at 9C (48F), and Edinburgh and Belfast at 8C (46F), while London is predicted to reach a high of 5C (41F), with Cardiff edging towards just 4C (39F).
The imminent arrival of the colder conditions comes as the Local Government Association's (LGA) annual winter readiness survey shows that councils are well prepared for plummeting temperatures with a substantial stock of grit.
About half are at the limit of storage capacity, and the LGA said gritters will be out treating thousands of miles of roads whenever overnight temperatures drop below zero in the coming days.
LGA transport spokesman Martin Tett said: "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."
Public Health England has also warned people to remember that "cold does kill" even in places that are not experiencing the coldest temperatures.
December 1 marks the beginning of meteorological winter, which lasts until February 1.