Icy conditions have caused travel disruption to some parts of the country following snowfall across the UK.
The worst-affected area was north-west England, where flights and rail services have been hit by delays and cancellations.
The Met Office has issued a fresh yellow warning for ice which will come into force at 18:00 GMT on Wednesday.
Motorists have been warned to take extra care because of hazardous driving conditions.
Forecasters said some parts of the country could expect further wintry showers later in the day.
The runway at Liverpool Airport was temporarily closed due to icy conditions, causing some flights to be delayed. Passengers were advised to call their airline before travelling.
Passengers using Manchester Airport also faced delays because of thick freezing fog, and two flights were cancelled.
The airport said the number of landings and take-offs had been reduced, meaning flights were being delayed by 20 minutes on average.
Merseyrail said there was severe disruption to its services caused by ice preventing electricity from reaching the trains.
Loving the train manager on @VirginTrains this morning. He’s just told everyone to take thirty seconds to look out of the window to appreciate the beauty of the countryside covered in snow “before we all get cheesed off with it”— Clare Balding (@clarebalding) January 23, 2019
Icy conditions have also caused a number of incidents on motorways in the North West, with the M61, M53 and M6 all affected.
In Wales, Dyfed Powys Police said it had received "several reports" of crashes due to ice while North Wales Police said snow was causing "treacherous" conditions.
There was a serious crash in Neath Port Talbot and a 10-car crash in Swansea on Wednesday morning.
The Met Office's new weather warning for ice is in place from 18:00 GMT on Wednesday until 11:00 GMT on Thursday, and covers large parts of the UK.
It has warned of ice on some roads, pavements and cycle paths, as well as an increased risk of slips and falls on icy surfaces.
Forecasters had predicted the coldest night of the winter so far, and temperatures dropped to -10.2C in Braemar, Aberdeenshire.
BBC Weather presenter Carol Kirkwood said south-east England had seen more snow on Wednesday morning, while Wales, Northern Ireland and Scotland could also get further wintry flurries.
She said the biggest hazard was ice, which was widespread across the country.