Met Éireann is predicting heavy rain from 1pm on Tuesday in Galway, Mayo and Donegal.
The warning will remain in place until 1pm on Wednesday.
The forecaster says there is a chance of localised flooding and poor driving conditions are expected.
In the rest of the country is in for a cloudy but mainly dry day in comparison, with maximum temperatures of between 17°C and 20°C expected.
The clouds and showers are likely to persist for the remainder of the week, with a threat of thunderstorms on Saturday as temperatures increase to a maximum of between 21°C and 24°C.
