A thunderstorm alert will remain in place for Carlow and Kilkenny until 10 pm tonight.
Parts of Leinster and Munster are also affected by the orange warning with some more heavy showers and thunder forecast.
Emer Flood of Met Eireann says the heatwave is now officially over.
“There will be some sunshine at times this week, but definitely, yesterday (Sunday) marked the end of the hot weather,” said Emer.
“You’re looking at temperatures in the mid to high teens for the rest of the week, maybe reaching the low twenties locally at times, definitely a much cooler and fresher week”.
Meanwhile, some power outages have been reported following the thunderstorm activity.
There are a number of small pockets without power (as of 10 am Monday) including Purcellsinch in Kilkenny city, the outskirts of Callan, parts of Bagenalstown and Tullow.
ESB networks say all of the local areas affected should be restored by this afternoon at the latest.
A large part of Castlecomer was without power earlier this morning but that was quickly resolved.
