Gardai in the region are warning people to drive with extreme care due to heavy fog in many parts.
Gardai in Carrick say the R263 between Killybegs and Glencolmcille has very heavy fog.
Visibility is very poor and people are urged to use their lights at all times.
Fog is also heavy on the N4 via Castlebaldwin to Carrick-on-Shannon.
There are also pockets in south Sligo and Leitrim and again people are asked to slow down and drive with care.
Gardai warn there is also black ice in many places especially in south Donegal.