The warm sunny weather will continue over the weekend in most of the State, according to Met Eireann.
While Britons gear up for weekend temperatures reaching 30, the seasonal sunshine in Ireland will fall short of a heatwave, a spokesman said.
Temperatures today are expected to remain in the mid-20s, but cloudier conditions in the west this afternoon will spread inland, bringing some patchy drizzle and fog to many areas.
Cooler air spreading from the Atlantic throughout the afternoon means temperatures in much of Connacht, west Ulster and parts of Munster will not rise above 18.
"This weak front will bring a temporary disimprovement. It will stall in the midlands and push back by late in the evening, and by Sunday, warm sunshine should re turn to all places with some cloud, mostly in the midlands," forecaster Mr Vincent O'Shea said.
"It's not really a heatwave. There are definite signs that the weather will cool off again on Monday and it will be mixed again during the week." Sunbathers are advised to be careful as the burn factor will be down to between 20 to 30 minutes in many areas.
Kilkenny and Birr, Co Offaly, were the warmest parts of the State yesterday, with temperatures up to 24. Onshore breezes kept temperatures lower in the east, with Dublin temperatures peaking at around 19. Breezes and sea fog in the south also kept temperatures in the mid-teens. Average temperatures so far this month have struggled to get above 16 or 17.
In Britain, forecasters have predicted temperatures between the late 20 Celsius. However, Scotland will be more cloudy and temperatures will not be as high as the rest of Britain.