"In Scotland, there is a flow of showers coming from the northwest turn into sleet and snow. For England and Wales, it should clear and get colder tonight, with a risk of ice almost anywhere and freezing fog patches.
"Even a "widespread frost" is expected overnight," said John Lee, a forecaster for MeteoGroup.
The Met office has issued yellow weather warnings for ice for most of Scotland this morning, but with a weather front drifting in from the Atlantic, the rain falling across much of England and Wales could also freeze tonight.
There could be a light dusting over the highest of the Peaks and Staffordshire but it won't be very long-lasting, the Met office said.
Tomorrow is expected to be clearer with some sunshine, but temperatures as low as two degree Celsius in much of central England.
