A yellow status rain warning has been issued for Cork and Waterford and will remain in place overnight.
The warning began shortly after 7am on Tuesday and will stay in effect until 7am on Wednesday.
Met Éireann said the counties will see "rainfall accumulations from heavy showers or longer spells of rain today and overnight".
The forecaster added some areas may experience isolated thunderstorms and spot flooding.
Rainfall accumulations from heavy showers or longer spells of rain today and overnight with isolated thunderstorms and spot flooding
Affected Regions: Cork and Waterfordhttps://t.co/Xg3aMJlyuS
Valid Tuesday 6/9/2022 07:17
Wednesday 7/9/2022 07:00 pic.twitter.com/V17A97wbav
— Met Éireann (@MetEireann) September 6, 2022
The two counties were also placed under a yellow warning on Sunday as heavy rain and strong southeasterly winds hit the south coast.
Elsewhere, a mostly cloudy and dull day is predicted for the rest of the country, with rain spreading to the north as the day progresses. Maximum temperatures are estimated to be in the region of 17-20 degrees.
Cloudy conditions and scattered showers are likely to hang around for the remainder of the week, with temperatures staying in the region of 16-20 degrees.