Snow has begun falling in parts of southern England, prompting fears of ice and disruption in the Monday morning rush hour.
There was expected to be a covering of up to six cms (2.4ins) in some areas.
Paul Mott, a senior forecaster with MeteoGroup, the weather division of the Press Association, said: "We are starting to see some snow in the south Midlands and over the hills of Surrey.
"There was snow earlier today over parts of Scotland and north-west England, mostly over the hills.
"We expect to see snow over northern parts of southern England, north of London, up towards the Midlands, and North Wales, and there are likely to be 2cm-5cm of snow in places overnight."
The falls are expected to stop by the morning, but the accumulations could still cause disruption for commuters.
More light flurries are predicted for Monday and Tuesday, after which the week is expected to turn milder.
Thousands of passengers have been stranded in America after flights to Britain were grounded when a massive snowstorm hit the US east coast.
Heathrow Airport said 10 inbound flights - all from New York and Boston - were cancelled, as was one outbound flight, to Washington. British Airways, Virgin Atlantic, Delta Air Lines, United Airlines and Air Canada were all forced to cancel flights on Sunday, Heathrow said. Passengers were advised to check if their flights are affected with their airlines.