No sign of widespread school closures though.
Met Éireann has issued a new Status Orange freezing fog warning for Dublin.
It's one of 21 counties where dense freezing fog is expected to persist, with very hazardous driving conditions forecast.
Meanwhile, a nationwide Status Yellow low temperature/ice warning remains in place until Friday.
The majority of schools have remained open, but they will carry out their own risk assessments as the week progresses.
Paul Crone, director of the National Association of Principals and Deputy Principals, says it's up to individual schools to make the call;
"They would decide with their maybe senior leadership team, their with board of management. They would get advice maybe from people who are living locally...to make sure that is safe for people to get in and out of the school, that the heating is working correctly, that the electricity is working fine, and that they would have their winter plan in place."
A number of flights at Dublin Airport were cancelled or delayed again today, mainly due disruption at UK airports.
Passengers are urged to get in touch with their airline to check the status of their flight.
While motorists are also being reminded to take extreme care, with the freezing fog adding to the icy conditions on the roads.