Winter is set to sweep in on Tuesday with widespread snowfall up to 15cm (6ins) deep threatening to bring travel disruption.
Temperatures fell as far as minus 5°C (23F) in central England overnight, bringing frost to most parts before the arrival of sleet and snow from the west later.
Forecasters have issued a weather warning covering much of Scotland and northern England to come into effect from midday, with cold and wet conditions expected to continue until Wednesday morning as a band of wintry weather moves slowly eastwards.
Drivers are being urged to take care as snow falls to lower levels overnight, with 4cm to 8cm (1.5ins to 3ins) across hilly areas above 200 to 300 metres, with as much as 15cm possible above 300 to 400 metres. Meanwhile there is a risk of gales of up to 50mph developing in the south west on Wednesday before moving along the Channel.
"We have had a few wintry showers but this is the first event where more people are going to be affected," Met Office forecaster Emma Sillitoe said. "There is a frontal system moving in from the west meeting the quite cold weather we have been having over the last few days.
"A yellow weather warning will be in place from 12pm today until 9am tomorrow covering high ground from Scotland down the east coast to the Midlands and we could see snow to lower levels below 200 metres of around 2cm (0.7ins).
"Obviously there will be a risk of difficult driving conditions on high routes over the Pennines and in Scotland and people will have to scrape the frost from their windscreens so it will be quite slow getting out and about on Wednesday."
Pershore in the West Midlands saw temperatures fall to minus 5°C (23F) overnight, while much of northern England saw the mercury hit freezing (32F) and 2°C (37F) in the South.
On Tuesday temperatures are expected to reach a maximum of 8°C (46F) in Northern Ireland and Scotland, 5C (41F) in northern England, 7°C (45F) in southern England and 11°C (52F) in the South West.
Freezing temperatures and frost are expected to return as the wintry weather clears to the east overnight before a return to similar daytime figures on Wednesday.