Donegal County Council gritters are to be deployed on all major road routes in the county from 9pm this Monday evening.
Temperatures are expected to fall below freezing tonight as forecasters warn of a risk of frost and wintry showers.
A Status Yellow snow-ice warning is issued for Donegal from midnight Tuesday to 12noon Wednesday.
Met Eireann has forecast sleet and snow showers in northern counties, mainly on higher ground but at some lower levels. Snow may lie in areas below 250m.
Temperatures as low as -1 to 3 Celsius are expected with widespread frost and icy patches.
There is also a chance of thunder with heavy downpours during the night.