Met Éireann has issued a status yellow rainfall warning for counties Waterford, Wicklow, Galway, Mayo, Cork, Kerry and Wexford.
The national forecaster has warned of "intense rainfall", with 25 to 40mm expected, and localised flooding.
The warning was issued today and it comes into effect at 9pm on Tuesday evening, valid until 12pm on Wednesday.
Met Éireann said: ”Heavy and at times intense rainfall with totals of 25 to 40mm expected.
”This may result in localized flooding. The rain will clear western counties by early Wednesday morning."