The low was recorded at Altnaharra in Sutherland, while minus 7C was recorded at Aboyne in Aberdeenshire.
In Aberdeen itself the mercury dropped to minus 5C, while the same low was recorded as far south as Cavendish in Suffolk.
A yellow warning of ice for most of Scotland, all of the North of England and down across to East Anglia is in place until 11am.
Met Office meteorologist Ellie Creed said: “It’s been pretty cold overnight and there have been showers in the last 24 hours, so there could well be some icy stretches around.”
For the rest of Thursday, an area of cloud, rain and hill snow over much of central England will move out towards the south.
Areas behind the band of wintry weather, particularly in the North East of England, could see some sunny spells.
However, cloud, rain and stronger winds will arrive from Northern Ireland to affect western parts later on - although temperatures will be milder with highs around 10C (50F).