Wexford and Waterford, along with parts of Carlow, Kilkenny and Tipperary will see temperatures hit 23 degrees today.
This comes as temperatures get set to rise steadily for the next five days and bring Ireland into a rare August heatwave.
Many counties will see temperatures above 20 degrees today, with large swathes of the midlands and south to see 22c but it will be a few degrees cooler in the west and northwest.
As the week progresses, a mass of high pressure will see temperatures consistently rise, nearing or exceeding 30 degrees in parts of the south and midlands by Thursday or Friday.
This will mean certain counties in Ireland will be warmer than man sun holiday destinations this week - such as the Algarve, the Canary Islands and many European cities.
The sunny southeast and parts of the southwest look set for the highest temperatures but Met Éireann have said the Midlands will also see days in the high 20s.
All counties can expect highs in the 20s this week for a number of days as a result of the prolonged hot and dry spell.
On Tuesday, parts of Dublin, Limerick, Cork and Tipperary are expected to experience 25 degrees while much of the nation will notice an uptick in heat to 23 or 24 degrees.
It will also be much warmer than usual at night with Met Éireann reporting that night-time minimum temperatures will not likely fall below the mid-teens by Thursday night, right through the weekend.
Parts of the south and east will have temperatures of 26 degrees by Wednesday afternoon and temperatures will steadily rise towards 30 degrees as the weekend approaches.