Met Éireann has issued a Status Yellow rainfall warning for four counties in the south and west of the country this afternoon, Thursday, October 31.
The warning will be valid from 2:00pm tomorrow afternoon through to 2:00pm on Saturday.
The alert will affect counties: Galway; Clare; Kerry; and Limerick.
Meanwhile, the rest of today will be generally cloudy and misty, with scattered patches of light drizzle, but some heavy rain will affect the south-west.
Rain will be widespread for a time tonight and heavy in places, according to Met Éireann, which also forceasts some hill and coastal fog.
The rain will persist over northern parts of the country all night, but drier weather is expected over Munster before midnight, which will push into south Connacht and south Leinster before dawn.
Remaining overnight rain and fog will clear northwards tomorrow morning.
Some dry, bright spells will emerge for a time, but more showery rain will push in from the Atlantic, soon becoming widespread, giving some heavy and possibly thundery bursts in places.
Top temperatures will reach 12° to 15°, Met Éireann notes.