Mayo is one of 17 counties that has been issued with a Status Yellow Fog warning by Met Éireann.
This warning will come into effect at 4:00pm this afternoon, and will expire at 6:00am tomorrow morning (Thursday).
Patches of fog and freezing fog can be expected, which will thicken this evening and tonight.
The warning covers all Connacht counties along with Cavan, Donegal, Monaghan, Dublin, Kildare, Laois, Longford, Louth, Meath, Offaly, Westmeath and Wicklow.
