It suits Sigur Rós that Dublin's sky is foreboding and ominous for the entirety of Sunday. As standard, their set is a slow burner. They have a better audience for open-air performance here than their previous excursions at Electric Picnic, where commanding the attention of a crowd split between the extremes of impatient drifters or devout fans is more difficult.

You get the impression that the three permanent members of Sigur Rós are not wholly bothered with anything at all, in the good way. A breezy serenity defines their sound and general attitude. Borrowing from this energy is a crowd that don’t stress themselves out unnecessarily, abiding happily by an eerily extended preamble.

In time they drop, offering a massive wall of sound backed by monochrome light and dotted LED portraiture. The band set up is more stripped back than earlier visits. They’ve lost a host of violinists and choral singers but maintained the orchestral sound, with headman Jonsi Birgisson carrying their absence with sustained falsetto and his bowed electric guitar.

Shortly before the set, a rainbow breaks through the drab weather. This nicely illuminates the Pride hangover that most attendees are wearing, but it also has the effect of being vaguely magical, as though the dark Nordic clouds overhead have brought some sorcery with them. Sigur Rós keep up this enchanted momentum, not letting the set get dominated by either entirely old or new tracks. It's a balanced build of momentum that ends majestically on Popplagið but doesn't apologise for itself with an encore. Instead, bassist Georg Hólm flings his guitar at the ground when they finish. "You don't see that enough any more," says one bemused spectator, in appreciation of their gear-wrecking.

Although they could have benefitted from the ether of an earlier nightfall, they still subdue and instil the Kilmainham grounds. Stepping out afterwards, the rest of Dublin seems indefinably less otherworldly, and disappointingly real.