A status yellow rainfall warning has been issued for three countries in the west and north-west.
Met Éireann is predicting heavy rain from 1pm tomorrow for Galway, Mayo and Donegal with the warning in place for 24 hours.
The forecaster says there will be the chance of localised flooding and poor driving conditions are expected.
"Heavy rain with accumulations between 30 to 50mm expected, potentially higher amounts possible in mountainous areas," they forecast.
Met Éireann are also warning that weather conditions "conducive to the spread of potato blight will develop on Tuesday evening and night and will continue through the rest of the week".