Met Eireann has put a flood warning in place as heavy thunderstorms are forecast for tonight.
The south and east of the country will be worst effected.
They will see up to 50 millimetres of rain expected to fall there over the next 24 hours.
Dublin City Council says it has closed the flood gates on the river Dodder in the Sandymount/Ringsend area as a precaution.
The weather service says rain will become widespread for a time tonight with some very heavy falls in places.
It will become windy in coastal areas and there is a danger of some flooding especially in coastal counties of the south and south-east.
But the rain will turn more showery later and some mist may form around dawn.
Pat Clarke is a forecaster with Met Eireann.
He says there is also a risk of further flooding tomorrow.