Winter 2020, meteorologically, started on 1 December and the weather looks set to reflect that.
Arctic air has started to plunge south over Ireland and the UK with ice, frost, and even snow in the forecast - albeit mainly for the tops of mountains.
A weather warning for ice has been issued across much of Northern Ireland on Wednesday night.
Temperatures will fall close to freezing almost everywhere.
Sub-zero temperatures are expected in some countryside areas.
The Met Office warning, which comes into force from midnight until 08:00 GMT on Thursday, says that icy patches could cause some travel disruption.
Frequent showers are expected overnight, especially in the north and west, which will allow some ice to form on roads and pavements.
Some of the showers are also expected to turn wintry with lying snow possibly over the tops of hills and mountains.
In the Republic of Ireland the Irish weather service Met Éireann has also issued a snow and ice warning for County Donegal for Thursday.
A sharper frost with a risk of ice is expected on Thursday night with temperatures falling several degrees below freezing, even in towns and cities.
The cold air is expected to last through until next week at least.