Most of the country will have a covering of snow over the next couple of days, forecasters have said.
Wintry showers started in the north-east of Scotland on Saturday and are likely to spread throughout Sunday.
With the average temperature around 2C, the Met Office has issued yellow "be prepared" weather warnings for Grampian, Central, Tayside and Fife, the Lothians and the Borders, with further snow warnings for Strathclyde and the Highlands.
Around 5cm of snow is predicted, with more in higher areas, and ice warnings have been issued for much of the country. Rain and sleet is forecast before any snowfall.
Julian Mayes, a forecaster with MeteoGroup, the Press Association's weather division, said: "Some wintry showers have been falling in higher parts of the Grampians and in Aberdeenshire, while temperatures have struggled to get above freezing in Inverness and the surrounding area.
"The average temperature for the rest of the country has been around 2C, dipping below freezing overnight, and it will stay that way as a large area of snow, sleet and rain moves into the south and west of the country early on Sunday morning. By dawn the showers will be moving inland and with temperatures remaining low it will be cold enough for snow in large areas, probably with sleet falling at sea level."
By Monday "significant accumulations" are expected and people are advised to plan their journeys adequately and take care when travelling.
Transport Minister Keith Brown has chaired a meeting between operating companies, Transport Scotland and the Met Office to discuss preparations for the weather.
He said: "After a mild spell the Met Office say we are now heading back into colder conditions. That means 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. The Traffic Scotland Control Centre continues to monitor the travel situation very closely."