Temperatures could reach 28 and possibly 30 degrees in some places today.
However thunderstorms are expected this evening.
Met Eireann have issued a yellow thunder weather warning which comes into place from 4pm until 9am tomorrow morning.
Mount Dillon in Co Roscommon has recorded the highest temperature in the country today, at 22 degrees at 12 noon.
Claremorris was 20 degrees, with 19 degrees in both Newport and Knock at 18 in Belmullet.