Met Éireann has issued two weather warnings ahead of the bank holiday weekend.
A status yellow warning for snow-ice will be in place in Co Donegal tomorrow between midnight and noon.
Heavy rain is expected to turn to snow on Friday night and early Saturday morning. This will lead to poor driving conditions in the county.
Snow accumulations are likely to be greater on higher ground.
Meanwhile, a status yellow warning for rainfall has been issued for 15 counties for tomorrow.
Connacht, Longford, Offaly, Westmeath, Cavan, Monaghan, Clare, Cork, Kerry, Limerick and Tipperary are expected to see heavy rain from 9pm tonight until noon tomorrow.
The rain will develop overnight and into Saturday. 25-35mm of rain is expected to fall, with some areas seeing spot flooding.
The rain may turn to snow in parts for a time.
St. Patrick's Day looks set to be a cold and blustery day with sunny spells and passing showers, some with hail and thunder.
Showers will retreat to coastal areas in the west on Sunday night. Good clear spells will develop elsewhere.
It is expected to be a rather cloudy day on bank holiday Monday, with scattered patches of light rain or drizzle.