Motorists in Scotland are being urged to exercise caution as a band of snow moves across the country.
Earlier drivers in the south-west were urged to “avoid unnecessary journeys” following a spate of road accidents.
Police said heavy snowfall across Dumfries and Galloway was causing problems on roads including the A75, which was blocked just outside Dumfries for a time.
A Met Office yellow weather warning for snow and ice is in force until 18:00.
In the south-west, the A75 Grenta-Stranraer road was blocked at the Glen as vehicles were unable to get up the hill.
Police later said it had been gritted and was “passable with care”.
Heavy snow was also affecting the A76, the A701, the A709 and the A713 Castle Douglas – Ayr road, where there were a number of accidents.
In their latest statement, police in Dumfries said: “If you are having to drive, please slow down and drive to the conditions.”
Traffic Scotland also urged drivers to check their routes before setting off and to ensure they were carrying emergency supplies in case they get stuck.
Glasgow Airport was closed for a short time while the runway was cleared of snow.
North Wales Police also warned of poor conditions on the roads due to snow and ice, particularly on routes in Snowdonia.
Meanwhile, the Mountain Road was closed on the Isle of Man due to snow.
In Northern Ireland, a yellow warning of ice was in force until 09:00 on Sunday, while a yellow warning of rain runs until 3pm.
The yellow “be aware” warning covers much of inland Scotland, and was later extended to cover the north-west Highlands and parts of the Western Isles.
Large swathes of England may also be affected, with areas as far south as Hertfordshire, Essex and Suffolk covered by the warning.
BBC Scotland Weather’s Christopher Blanchett said the band of snow, sleet and rain would move north-east across Scotland on Sunday.
“Expect a centimetre or two to low levels; 10cm or more on ground above 300m,” he added.
The Met Office’s chief forecaster said most of the expected snow would fall on higher ground and snowfall would vary considerably across the warning area.
He added that rain could fall on frozen surfaces following a “very cold night”.
“Some roads and railways likely to be affected, with longer journey times by road, bus and train services,” the forecaster said.
“Some injuries from slips and falls on icy surfaces. Probably some icy patches on some untreated roads, pavements and cycle paths.
“The snow is expected to become confined to northeast Scotland later in the day as it progressively turns to rain from the southwest.”
Saturday night saw the coldest temperature recorded in the UK since February 14 2016, when minus 14.1C was recorded at Braemar.
Despite the frigid temperatures in the far north, the mercury rose to 11C in the far south west of England.
Met Office forecaster Steven Keate said the near 20C difference, caused as warmer air moves in, was “pretty unusual for the UK”.
“The broad theme is it is turning milder from the west, but before we get there some snow will fall,” he said.
