Met Eireann has extended a Status Yellow Warning for fog until tomorrow morning.
The alert came into effect yesterday afternoon and was due to expire this morning.
Status Yellow - Fog warning for Ireland
Update: Fog will be slow to lift and will linger in some parts for much of Saturday. Becoming widespread and dense again on Saturday evening, but retreating to northern areas by Sunday morning.
Valid until Sunday 9 a.m. pic.twitter.com/fGZIeNF5mK
— Met Éireann (@MetEireann) December 21, 2019
However, the forecaster says fog will linger in some parts for much of today and become widespread and dense again this evening.
Meteorologist Cathal Nolan says road users need to be particularly careful.