Police dealt with 25 road crashes in just one hour as freezing conditions were felt across much of Scotland on Monday morning.
The Met Office said the lowest temperature recorded overnight was minus 9.8C at Strathallan, Perthshire.
The cold weather also led to disruption on rail services with trains unable to stop at Johnstone in Renfrewshire due to icicles on the overhead lines.
Several schools were closed to pupils because of heating or water problems.
At 08:00 on Monday, police tweeted: “Road traffic collision reports are coming in fast this morning … 25 in the last hour alone.
“These sometimes cannot be avoided, but please remember that stopping distances can be up to 10 times longer in icy conditions.”
The mercury dropped to minus 9C at Glasgow Airport and minus 8C at Edinburgh Airport overnight.
ScotRail later tweeted an update about the problems at Johnstone, saying staff had removed the icicles.
In Fife, three schools – Pitcoudie Primary, Buckhaven Primary and Kilmaron School – were closed due to issues with their heating or water systems.
Highland Council said Grantown Primary and nursery and Tarradale Primary and nursery would remain shut on Monday.
In Dumfries and Galloway, Laurieknowe Primary in Dumfries and Glenluce Primary in the west of the region were also closed.
Forfar Academy in Angus was closed at 10:45 due to heating issues and Whitecross Primary School near Falkirk was shut because of a heating system failure.
East Renfrewshire Council said it would reopen St Clare’s and Calderwood Lodge primary schools in Newton Mearns – which were closed due to heating issues – after lunch, at 13:35.
The cold snap is expected to ease slightly over the coming days.
Ian Robinson, of the Met Office, said: “We’ve started to see a pick-up in wind speed from the south and there should be a cloudy spell of weather coming.
“The very low minimums of the past few days are probably not going to be repeated.
“It may be down to minus 3C tonight but generally minimum temperatures will not be as low due to increasing wind and cloud.”