Met Éireann has confirmed today as the hottest day of the year.
The forecaster says the heatwave is set to continue in the days ahead - and could last until next week.
Met Éireann has issued a "Yellow Temperature Warning", asking people to stay protected in the heat.
Yesterday had been the hottest day of the year, with temperatures reaching 28 degrees.
"It looks like it's going to beaten - at the moment we have a temperature of 29 degrees in Roscommon," said Harm Luijkx of Met Éireann.
"It's hot in most places, and most parts of the country have high temperatures … 28, 29 degrees."
"The majority of the country is very hot."