The Met Office has issued a "yellow" warning of severe weather for parts of Scotland as temperatures plummet.
Forecasters said the cold snap was likely to bring widespread ice, with temperatures expected to drop to -6°C in some places.
Alerts are in place for Grampian, Tayside, Fife, Central, Lothian and Borders, and south-west Scotland.
Today is expected to see a light dusting of snow in some places, but it is expected to get heavier tomorrow, bringing as much as 4in of cover.
A Met Office spokesman said: "On Saturday there will be outbreaks of rain and sleet with some snow.
"On Sunday morning, the showers will turn to light snow. Snow showers are likely to affect Scotland and northern England and on Sunday we could get 5cm to 10cm [2in to 4in]."
Transport Minister Keith Brown said: "Drivers will have to be on their guard more than ever, especially when driving in freezing conditions.
"A number of improvements have been introduced to help inform decision-making. This includes having more salt in stock or on order than ever before, additional gritters and specialist equipment, new weather stations and cameras, and improved communications."