The Met Office says a temperature of -6.1C was recorded in Altnaharra in the Highlands.
NatureScot says a Highland estate could be targeted with Scotland's first deer control scheme.
Altnaharra in the Highlands recorded the lowest overnight temperature of the winter in Scotland.
Warnings of potential problems across many parts of Scotland are in place on Saturday and Sunday.
Temperatures in the Scottish Highlands fell to -15.4C as a Met Office snow and ice warning remains in force.
Parts of the Highlands, Moray, Aberdeenshire, Tayside and Fife are covered by the Met Office warning.
The Met Office has confirmed snow fell in parts of Scotland on 25 December as weather warnings were extended.
The Met Office has issued weather warnings for parts of Scotland for Wednesday and Thursday.
Lucy Creaney's husband Finn has now been missing seven days after setting out on a hill walk.
