Temperatures were forecast to fall to freezing on Wednesday night, while a status yellow rain warning is in place for Cork and Kerry on Thursday night.
Met Éireann said there would be spells of heavy rain in those regions from 11pm on Thursday until 12pm on Friday.
Met Éireann said Thursday will start cold, bright and mostly dry with just isolated showers.
However, cloud will build from the southwest through the morning and the showers will become heavier and more frequent for the afternoon as they move northwards across the country.
Rain will develop in the southwest by early evening. The highest temperatures will be 9 to 13 degrees with light to moderate south to southeast winds.