Met Éireann has issued a yellow rainfall warning for all counties this Sunday.
The warning is set to start at 2am on Sunday and last until midnight on Monday.
Met Éireann has said that high amounts of rainfall may cause some disruption and spot flooding, with highest amounts in mountainous areas.
It will be mostly dry at first on Saturday night, but cloud will thicken from the south overnight and outbreaks of rain will spread across Munster and Connacht before dawn.
Lowest temperatures will be of 11°C to 14°C in a moderate southeast breeze.
On Sunday, rain will extend nationwide, turning heavy and persistent with the possibility of localised flooding.
Maximum temperatures of 17°C to 20°C in fresh south or southeast winds.
There will be further outbreaks of rain overnight, again with the continued potential for spot flooding.
It will be mild and humid overnight, with lowest temperatures of 13°C to 16°C.
Met Éireann has said that the outbreaks of rain will gradually ease and clear on Monday, with dry and bright periods developing. Maximum temperatures of 17°C to 22°C.