Met Éireann has issued a Status Yellow weather warning for rain for Donegal, Galway, Leitrim, Mayo, Sligo, Cork and Kerry.
The forecaster said that prolonged rain today and tomorrow is likely to cause heavy downfalls to the counties affected in Ulster, Connacht and Munster.
Rain is expected to be heaviest and most persistent later tomorrow.
According to Met Éireann, significant accumulations are possible in upland areas, and there is a risk of localised flooding.
The weather warning is valid until 3am on Saturday, with drier and cooler weather expected later in the weekend.
Some heavy and persistent rain for western areas today & tomorrow as a weather front stalls across the country - rain warning in place ??— Met Éireann (@MetEireann) October 7, 2021
This rain may edge across to eastern areas at times too ???
Drier & cooler weather on the way later this weekend ???? https://t.co/J3Suep6kNa