Met Éireann has issued a status Orange low temperature warning for many counties, with temperatures set to plummet to as low as -6C tonight.
The warning is valid for Munster, inland areas of Leinster and Connacht, as well as counties Donegal, Monaghan and Cavan.
Met Éireann has said temperatures will turn "very cold", with lows of between -4C and -6C.
They have also warned of "severe air and ground frost".
The warning is valid until 10am tomorrow morning.
AA Roadwatch reported black ice on the N71 Cork/Bandon Rd between between Skibbereen and Clonakilty as well as on the Midelton/Dungourney Rd (R627) at Ballinacole Cross.
Tomorrow will continue cold and icy with temperatures staying low, between 3-8C.