Snow is falling in London as up to 15cm blanketed some areas of the rest of the country.
England, Scotland Wales and Northern Ireland have all seen rain, sleet and snow on Thursday.
Met Office snow and ice warnings remain in place for the majority of the UK until midday but forecasters say the weather system will move on by the afternoon.
People have reported snow falling in London, while others have shared photos of dustings in Oxfordshire and Cambridgeshire.
In London, large flakes have been falling this morning, although the Met Office said it was mostly quite wet and unlikely to settle.
Social media users have shared videos and photos of flurries sweeping through the city as wintry precipitation continues through the morning.
Met Office meterologist Luke Miall said that Loch Glascarnoch in Scotland saw up to 15cm of snow by 6am.
Meanwhile, Lake Vyrnwy in Wales has seen at least 5cm and Leek in Staffordshire has had 6cm of snowfall, he added.
Some roads and rail networks in the north and Wales are facing disruptions due to the weather but the majority of routes are operating as normal.
Mr Miall said: "During the night we have seen an area of rain, sleet and snow pushing across some southern and central parts of the county."
"But it is the north and northwest of the country that have seen the heaviest amounts of snow."
He added that the largest amounts of settled snow have covered higher grounds in Scotland, Northern Ireland, northern England and the North Midlands.
"Oxfordshire and the South Midlands have reported snow but it is mainly wet stuff and so it is unlikely to settle on the ground - maybe cars and grass but not on the roads." Mr Miall said.
"North London is right on the periphery of where this rain and snow devide is so there have been reports of snow in London but this snow is more wet and not likely to settle."
Mr Miall said the weather front itself will have moved on by Thursday afternoon with the rest of the morning seeing some smaller outbreaks of sleet, snow and rain.
But by lunchtime the system will have cleared over the east coast and it will start to warm up as the sun arrives, he added.
Temperatures had dropped to -4C in Scotland and 1-4C in the south overnight, but Brits can expect the mercury to rise over the next few days.
However, the weekend is set to be very windy with the potential of gales up to 50mph, so it will still feel very cold, Mr Miall said.
