Met Éireann has updated a status yellow weather warning for heavy rain in Galway which will begin tonight at 3am.
Heavy rain with isolated thunderstorms are forecast across the country, which could cause disruption and localised flooding.
The warning comes into effect in all counties at 3am on Sunday morning, and will remain in place for 24 hours.
It will be humid and breezy on Sunday with highest temperatures of 17 to 20 degrees in fresh southerly winds.
On Monday, patchy rain and drizzle will become largely confined to the southeast of the country with sunny spells developing elsewhere.
Met Éireann has issued a status orange warning for Cork and Waterford for Sunday.