The heatwave is continuing today with temperatures to reach as high as 31 degrees in parts.
A status orange warning is in place for Cavan, Monaghan, south Leitrim, Roscommon, Longford and Westmeath.
☀️ Solar UV index for Wednesday ☀️
— Met Éireann (@MetEireann) July 21, 2021
Meanwhile, the rest of the country is under a similar status yellow alert.
Both will run until Friday.
It comes as parts of the world are experiencing severe weather events like flooding in Germany and high temperatures in Canada due to climate change.
Met Eireann says today and tomorrow will be the hottest days of the week with temperatures expected to drop on Friday.
While today is promised dry, clouds from the southwest will turn the sunshine hazier at times.
High temperatures may spark off a few thundery showers across north Connacht and Ulster later in the afternoon.
Met Eireann expects temperatures to reach 27 to 30 degrees today.