Northern Ireland could experience snowfall over the coming days, forecasters said today.
The Met Office has issued its yellow "be aware" warning for much of Scotland and Northern Ireland for today and tomorrow.
"Icy stretches are expected to form on untreated surfaces, especially in places affected by showers," a spokesman said
"The showers will fall as snow above about 250 metres, but there may be temporary slush deposits to lower levels. The public should be aware of possible travel disruption.
While the past few weeks have seen unseasonably mild weather across tUK, temperatures are set to plummet by this weekend.
Snow was falling over high ground in Wales, northern parts of England and Scotland today but was not expected to settle, while wintery showers and hail are expected to be widespread tomorrow.
A spokeswoman for the Met Office said there was a chance of snow across the country by early next week.
An Atlantic weather system is trying to push in from the west and would be coming up against cold weather in the east over the next few days.
"There is a degree of uncertainity about what it will bring in the early part of next week, but it looks like there is a good chance of snow," she said.
She added: "Temperatures will fall to below freezing tonight so motorists will need to watch out as roads are likely to be icy tomorrow.
"We expect there will be snow over the hills of north west and northern England and Scotland.
"Temperatures are only expected to be slightly lower than they have been, in England they will be around 7-8C and 5-6C further north, but will be much colder by Saturday - down to -2C or -3C in the south and -3C to -4C in the north and Scotland.
"Colder weather will continue but there is uncertainity about where the frontal system will go."
Nick Prebble, a forecaster with MeteoGroup, the weather division of the Press Association, said hail would hit much of the country tomorrow.
He said: "Tomorrow will feel a lot different to recent days, the main thing about it is there are going to be a lot of wintery showers all over the country.
"There may be snow flurries in higher areas but hail elsewhere.
"It will be quite a bright day though overall with quite a few sunny spells, around 8C in London."
He added that sleet and snow could be expected in eastern areas by Monday.