Met Éireann has issued a status yellow rain warning which will come into effect at 10pm on Monday in Galway, Mayo and Donegal.
Heavy rainfall on Monday night and for a time on Tuesday morning may cause localised flooding, the forecasters have said.
The warning is set to be lifted at 5am on Tuesday morning.
It will be a windy night too, with fresh to strong and gusty southerly winds veering westerly and easing as the rain clears.
Lowest temperatures of 12 to 14 degrees are forecast.