A Met Éireann thunderstorm warning is in place for the entirety of Leinster and Munster.
The forecaster later updated its status-yellow weather warning to also include the counties of Cavan, Donegal and Monaghan.
The warning came into force shortly after 2pm on Sunday and will last until 9pm tonight.
The areas under the warning are expected to experience localised thunderstorms with possible hail and spot flooding. "Treacherous" road conditions are also expected.
"Scattered heavy thundery showers about for the rest of the day, with the risk of lightning, hail and spot flooding, especially across Munster and Leinster," the forecaster said.
Status Yellow⚠️Thunderstorm warning for Leinster, Cavan, Donegal, Monaghan, Munster
Update: Localised thunderstorms with the risk of hail & spot flooding. Treacherous road conditions.
Valid: 16:43 Sunday 23/05/2021 to 21:00 Sunday 23/05/2021https://t.co/Xg3aMJlyuS pic.twitter.com/7MyRwRELZi
— Met Éireann (@MetEireann) May 23, 2021
Sunday is also expected to bring some sunny spells nationwide, though it will remain relatively cool with highest temperature of 11 to 14 degrees.
Tonight will bring clear spells and further scattered heavy showers, with some possibly thundery for a time early tonight.
It will be cold under any prolonged clear spells, with lowest temperatures of one to five degrees.
Monday will bring further showers with longer spells of rain in places. There will be dry and sunny spells during the day also, with highest temperatures of 11 to 14 degrees.