The mercury plunged to -8.8 degree Celsius in Katesbridge, County Down, in Northern Ireland, not out of the ordinary for December but setting a new low for the year after last winter's relatively mild and wet conditions.
The Met Office warned of icy driving conditions in eastern Humberside, eastern Lincolnshire and northern East Anglia.
The Highways Agency also advised motorists to be aware of driving conditions but no major disruption due to weather was reported on the roads.
A cold but dry day is expected across the UK with some winter sunshine and a lack of wind chill meaning it could feel relatively mild before temperatures fall overnight again.
Although it will be cold, temperatures are not expected to be as low as they have been, with the mercury forecast to be comfortably above freezing in Scotland and Northern Ireland.