The sun is expected to look kindly upon the 80,000 people at the concert in Slane today, the largest one-day music event of the summer.
The headline act, British singer Robbie Williams, is expected to receive loud adulation from a mainly teenage audience who, according to the organisers, are meant to be accompanied by an adult if they are under 18.
He is supported by an eclectic group of acts, among them the Happy Mondays, the Stereophonics and Placebo.
If the Met Eireann predictions for sunny weather (about 22 Celsius) hold up, the biggest bar ever assembled in the Republic will be badly needed, not to speak of nearly 600 Portaloos.
The Co Meath village was sealed off at 10 p.m. yesterday, with access restricted to residents. The first of the 80,000 concert-goers will be allowed in at 11 am. Simon Carmody, formerly with the Irish band Golden Horde, will aim to interest early arrivals.
Williams is expected to be flown into Slane this afternoon. He told BBC radio earlier this year it was "sacrilegious" he was higher up the bill than the Happy Mondays. He is believed to be anxious to watch their performance, between 4 and 5 p.m.
A large Garda force will be on duty during the day. The River Boyne, which runs around the back of the venue, has claimed the lives of some previous concert-goers. A Garda sub-aqua unit will be patrolling the area.
For a decidedly less mainstream musical flavour, the third year of the Liss Ard music festival began last night in the small town in West Cork. The 10-day festival, held a mile from Skibbereen, is to raise money for a local ecological project.
It has attracted big names with acts such as Australian rock poet Nick Cave, John Cale, Jello Biafra and the Afro-Celt Sound System lined up.