Met Éireann says the country will see the last remnants of sunshine today before the weather takes a turn tomorrow.
Temperatures are expected to drop down into the teens on Monday as a front from the west is set to arrive bringing morning showers to the west half of the country.
The rains will move eastward through the day with the potential to bring thunderstorms.
However, Meteorologist Eimear Flood says the warm weather should hold on for the rest of the day.
In parts of the midlands, temperatures could reach up t0 28°C or 29°C.
"There is a chance of a few showers this afternoon, one or two of them might even be quite heavy thunderstorms but they will be quite localised in the west if they do pop up," said Ms Flood.
"Otherwise, there will be plenty of warm sunshine with light north-west breezes as well."
Next week will begin with heavy or thundery bursts of rain at times which could lead to spot flooding in places.
The best of the sun will be found in the east early in the day where temperatures will be around 19°C to 23°C.
Further scattered showers will move in from the Atlantic on Monday night which will spread across the country through Tuesday turning heavy and more frequent as the day goes on.
It will still be quite warm despite the risk of localised flooding with highs of 20°C expected.
Wednesday will bring widespread heavy, possibly thundery showers with some sunny spells and temperatures dipping to 15°C to 19°C.
The showery heavy rain will continue on Thursday and conditions will remain unsettled through Friday and the weekend.