It was threatening all afternoon and, when it came, it came quickly. At 4.40pm, a torrent of hailstones fell on the thousands of music fans queuing patiently and with good humour to enter the Oxegen campsite at Punchestown racecourse in Co Kildare.
A huge roar of defiance went up as the hailstones came down in sheets driven by a squall. Within a few minutes it had passed and a strong sun came out, but only briefly.
Then it started to rain again, this time persistently. White metal sheets were placed on the approaches to the campsite, but no amount of preparation could compensate for the deluge of recent weeks.
As soon as the metal sheets ended, the quagmire began. The entrance to the blue campsite resembled an approach road to the battle of the Somme. Concertgoers, who unwisely brought suitcases on wheels instead of rucksacks, were forced to carry them, getting mud on their clothes in the process. A wheelbarrow full of booze tipped over into the mud and the Joe Bananas tent sold out of Wellington boots.
Some took refuge in the 24-hour Centra, a new addition this year, which at least had wooden floors. It did a steady trade in what is euphemistically called "hangover food" - packets of milk chocolate digestives, pot noodles, crisps, bars of chocolates and crates of Red Bull.
By early yesterday evening the Punchestown Racecourse site in Co Kildare which is hosting Oxegen '07 was already a mudfest to rival anything ever witnessed at Glastonbury and that was before any band had taken to the stage. The conditions forced the closure of the car park and all concertgoers coming from Dublin will have to use the park and ride facility at Goffs on the N7 today and tomorrow.
Luckily, the 80,000 revellers, overwhelmingly of college-going age, are nothing if not hardy and determined to defy the vagaries of the worst summer any of them can remember. The appearance of a rainbow elicited another hearty cheer and it was swiftly followed by another apocalyptic shower of hailstones.
Eoin Burke (18), from Cavan, said: "It's a bit depressing, but once you have a bit of love in the air, good spirit and alcohol, you'll get through it".
Laura O'Reilly (19), also from Cavan, said: "I'm loving it. As long as you have your wellies, you'll be all right."
Though it seems like a rather cruel joke given the conditions, the Ambre Solaire spray team, who will be offering festival goers free sun protection, may not be the most redundant people at Oxegen. Today is expected to mark a respite from the dismal run of bad weather with, brace yourselves, some sunny spells and even warm temperatures.
"There will be good sunny spells. There will still be a few showers passing by but, really in comparison with what we've been experiencing, it will be a lot drier," said Joanna Donnelly from Met Éireann. Sunday, though, will see a return to what we have come to expect, more heavy rain.
The action gets under way at 1pm on the main stage when British indie band The Cribs take to the main stage.