Met Éireann has issued a "status orange" thunderstorm warning for many areas of the country tonight and tomorrow.
The national weather service issued the thunderstorm warning for Munster, Leinster, Connacht, Donegal, Monaghan and Cavan.
"Some intense thundery downpours are likely at times, with possibly some flash flooding in places," the warning read.
Summertime! Some intense thundery downpours, possible flash flooding in places tonight & tomorrow All areas ( esp Connacht Ulster) this p.m
— An Garda Síochána (@GardaTraffic) June 9, 2014
It said Connacht and west Ulster were at greatest risk this evening.
An orange-level warning is for those weather condition which will "impact significantly on people in the affected areas".
The warning will remain in effect until 9pm tomorrow.