Met Éireann has said that rain will turn to sleet or wet snow late tomorrow morning and through the afternoon over parts of Connacht, south Ulster and north Leinster.
It said that there is a risk of snow falling on higher ground and perhaps at lower levels for a time also.
However, rain, sleet and snow will clear during the evening and early night.
Meanwhile, Britain's Met Office has issued a weather warning, with snowfalls of up to 10cm possible in some areas of England tomorrow.
It said conditions could "increase the health risks to vulnerable patients and disrupt the delivery of services".
The expected snowfalls threaten disruption on one of the busiest shopping days of the year in Britain.
