The national forecaster has issued a snow alert, and has warned of temperatures as low as -4C as the weather turns colder.
The alert covers the following counties: Galway, Leitrim, Mayo, Roscommon, Sligo, Cavan, Monaghan, Donegal, Dublin, Kildare, Laois, Longford, Louth, Wicklow, Offaly, Westmeath, Meath, Kerry, Limerick and Tipperary.
Friday will begin cold and dry, but a spell of rain will come in from the southwest, spreading northwards throughout the evening.