Met Éireann has issued a Status Yellow fog warning for Munster.
The forecaster said dense fog will develop in places tonight and linger tomorrow, leading to hazardous conditions on roads.
The warning is valid from midnight until 10am tomorrow.
The Road Safety Authority (RSA) has urged all road users to take extra care, saying dense fog seriously reduces visibility and makes driving conditions very dangerous.
Motorists are advised to switch on dipped headlights and fog lamps, reduce speed, and allow an extra safe distance from the vehicle in front.
The RSA said those who must drive in fog should allow plenty of extra time for their journey.
Before setting out, they should also check their vehicle is in good working order, particularly that all lights, including fog lights, work properly and are clean.
The RSA also advised vulnerable road-users such as pedestrians, motorcyclists and cyclists to ensure they are clearly visible to others by wearing high-visibility clothing and using lights.
⚠️#fog warning issued for Munster⚠️— Met Éireann (@MetEireann) November 22, 2021
Patches of fog will form overnight & tomorrow
Fog can lead to hazardous road conditions, so take care on commutes this evening and tomorrow morning 🚗🌫️https://t.co/l8JdKfwZt9 pic.twitter.com/ZfJcllGS4s