Temperatures could drop as low as minus four tonight as the cold spell continues.
A weather advisory is to remain in place until midday on Friday.
Met Éireann is warning of animal welfare issues and difficult travelling conditions.
Already KCLR Breakfast has been hearing of ice on many local roads.
Alan O’Reilly from Carlow Weather says the chilly conditions are here to stay; “Remaining cold up until Friday afternoon with very hard frost each night and cold temperatures throughout the day, it will turn less cold from Friday evening but unfortunately turning wet and windy for the weekend and a very unsettled spell of weather ahead for the weekend and next week”.