There will be showery and humid weather for much of today and tomorrow but it is unlikely to dampen the spirits of those looking forward to a big weekend of music and sporting events.
Met Éireann said temperatures will reach as high as 21 degrees in inland parts of the country today and remain in the high teens tomorrow, but that there would also be regular showers in most areas.
Veteran rockers TheWho kicked off the weekend's events at Marlay Park in Dublin last night, and they will be playing a sold-out show at the Marquee in Cork this evening.
A much-awaited five night stand of gigs by US rock group REM will get underway in the Olympia Theatre in Dublin tonight, where they will be supported by David Kitt.
The shows sold out within minutes of going on sale but the band have announced that a small number of tickets, limited to two tickets per person and priced at €50, will be made available on the day of each concert. They will go on sale at 4pm at the Olympia box office.
Their second show begins at 8pm tomorrow, while three other gigs take place between Tuesday and Thursday.
US pop star Justin Timberlake will play the first of two concerts tonight at the RDS in Dublin. He returns to the southside venue tomorrow before playing a late night gig in Vicar Street the same night.
The Cork Midsummer festival comes to a close this weekend and will include performances by Julie Feeney and the Sultans of Ping.
In sporting action, provincial finals in both hurling and football will take place tomorrow.
Kilkenny will be looking for their third title in a row when they take on Wexford in the final of the Leinster Hurling Championship at Croke Park, while in Killarney rivals Kerry and Cork meet again in the Munster football final, as Cork seek to defend their crown.
Wexford fans will be hoping their footballers can also reach a provincial final, as they take on Laois in the Leinster football championship semi-final at Croke Park tomorrow.
The All-Ireland hurling qualifiers will also begin today, when Ger Loughnane's Galway face Laois, Antrim take on Clare, Tipperary play Offaly and Dublin host Cork.
Sunday's Budweiser Irish Derby festival at the Curragh will be the highlight of a big weekend's racing.
Tomorrow's Derby will be the main attraction, where Eagle Mountain, trained by Aidan O'Brien, is among the favourites to win.
Met Éireann has said there will be some dry intervals throughout the country today but heavy, sometimes thundery showers too. Further rain overnight will be followed by heavy showers throughout Sunday.