Drivers are being urged to proceed with care this morning as there is frost and icy stretches in some areas of the county.
It comes as Met Éireann has issued a weather warning for snow and ice in Donegal tomorrow.
Temperatures are set to drop in the coming days with lows of -3C at night.
A band of rain will turn increasingly to sleet and snow on Thursday, forecasters warn.
The wintry weather will bring a risk of ice on untreated surfaces.
Motorists are warned to expect hazardous driving conditions, travel disruption and poor visibility.
The status yellow alert specifically for Donegal is in place from 11am until 8pm on Thursday.
Today’s weather
Meanwhile, it will be dry and calm with high hazy sunshine for much of the day across Ulster. It will be cold with highest temperatures of just 4 or 5 degrees with light northeast breezes.
Frost and ice will set in for a time tonight under clear skies. Overall dry and clear, though some to sleet and snow I possible in parts towards morning, mainly further south. Lowest temperatures of -3 to 0 degrees in a light to moderate easterly wind, freshening later.