Two separate Status Yellow rain warnings have been issued for parts of the south and southeast of the country.
Met Éireann is warning of spells of heavy rain from midnight tonight until 5pm tomorrow.
A Status Yellow rain warning for Cork and Kerry will be in effect from midnight tonight until 2pm tomorrow, with localised flooding and difficult travelling conditions forecast.
A second Status Yellow rain has been issued for Carlow, Kilkenny, Wexford, Wicklow, Tipperary and Waterford from 2am until 5pm tomorrow.
The forecaster is warning of the potential for localised flooding, difficult travelling conditions and poor visibility.
It will be a wet day for most parts tomorrow with spells of persistent and heavy rain in many areas.
A Status Yellow rain warning has also been issued for Antrim, Armagh, Down, Fermanagh, Tyrone and Derry. This is valid from 6am tomorrow morning to 9pm that evening. The UK Met Office warns of persistent and at times heavy rain may lead to some travel disruption and brief flooding of a few places.
Despite the heavy rain, it will be a mild day with highest temperatures of 11 to 14 degrees.
