A Status Yellow rainfall warning, which began yesterday evening, will remain in place until midnight tonight across Connaught counties.
The week is set for a cold and wet start, with a rainfall warning in place for 20 counties in total.
Heavy rain will continue over the coming days and parts of the country are expected to be liable to flooding as the wet weather sets in.
The weather warning is set to affect all counties in Connacht and Munster , as well as counties Carlow, Kildare, Kilkenny, Laois, Longford, Wexford, Wicklow, Offaly and Westmeath.
Forecasters warn that heavy rainfall will occur with the potential for frequent heavy downpours.