A Status Yellow fog warning was in place for the entire country, as dense patches led to reduced visibility and poor driving conditions.
Met Éireann said the warning was active 5.15am and ended at 10am.
Motorists were warned that some areas of dense fog may cause difficult travel conditions.
"Areas of thick fog probably causing some tricky travel conditions or delays this morning," the forecaster said.
Mist & fog will be slow to clear this morning⚠️🌫️— Met Éireann (@MetEireann) November 17, 2022
Many areas will stay dry with sunny spells but there will be scattered showers in the southwest & west & outbreaks of rain will develop in east Ulster during the afternoon & evening⛅️🌦️🌧️
Highest temps of 5 to 11 degrees🌡️ pic.twitter.com/onE5YHn4KI
The UK Met Office also issued a Yellow fog warning for Antrim, Armagh, Down, Fermanagh, Tyrone, Derry which came into effect at 4.40am, and ended at 10am.