The Met Office issued a yellow “be aware” weather warning for ice across London, the south east and south west of England, warning of the risk of injuries from slips and falls on untreated roads and pavements.
Temperatures fell well below zero in parts of the country, with Topcliffe in Yorkshire experiencing minus 5.2C, and Benson, Oxfordshire, having an overnight low of minus 4.9C.
A further weather warning for Northern Ireland and parts of Scotland and Wales, as well as the north of England, Yorkshire and the West Midlands, was issued on Friday night, with both warnings in place until 10am.
Snow and sleet are also expected in parts of the country throughout the day.
Met Office meteorologist Mark Wilson said: “The forecast is a day of sunshine and wintry showers, mostly across the north and west.
“It will generally be dry across the central and eastern parts of England.
“In the north and west of Scotland, the showers will be wintry at times and over higher ground we are likely to see snow, although it could fall on lower ground as well.
“It will be a cold and breezy day, feeling incredibly cold for November.
“Highs across the UK will be seven degrees at best, feeling colder in the wind. There will be a risk of ice throughout Saturday night into Sunday as well.”
The North West Motorway Police reported sleet and snow on the M62 in the early hours of Saturday, while police in Kent urged drivers to be careful on the icy roads.
Public Health England warned people to be prepared as forecasters predicted a prolonged spell of cold weather.
Dr Thomas Waite, of their Extreme Events team, said: “We’re well used to winter in this country so most people know what to do to protect their health before and during cold spells.
“But there are people who may not take precautions and who are at a very real risk.
“We know that every winter thousands of people fall ill and many die because of exposure to cold both in the home and while outdoors.
“Those most at risk include older people, very young children and those with conditions like heart and lung disease.”
Figures earlier this week showed there were more than 34,000 “excess deaths” across England and Wales over the last winter period, the second highest level in eight years.
The Met Office warned the cold weather would remain on Sunday, with a short-lived milder day on Monday, before a prolonged period of low temperatures throughout next week and the following week.