Met Éireann is forecasting "very warm" temperatures of up to 27C tomorrow, with "long spells of sunshine".
The forecaster said the day will start with "mist and fog patches", but it will turn dry with plenty of sunshine.
Temperatures, it said, will range from 22C to 27C, with the highest expected in Munster and Leinster.
Aside from the warm weather, Met Éireann has said the pollen level tomorrow will be "moderate" across all provinces.
It said the tree pollen count is at "medium concentrations", but added "moderate to high concentrations" of grass pollen levels are expected.
While weed pollen levels are low and moderate levels are expected for fungal spores, it added.
Met Éireann said temperatures on Tuesday are also forecast to reach up to 27C.
"It will be dry and although some cloud will affect the northern half of the country at times, there will be plenty of warm or very warm sunshine overall," it said.
"It will be cooler than this along north-facing coasts," it added.
The forecaster said temperatures will range from 20C to 27C.
However, Met Éireann has warned temperatures "will decrease later in the week, with showers becoming a possibility".
