Sunday August 9 was the first day of the Oslo Jazz Festival. It was cloudy and cool and rained off and on all day until, miraculously, the skies cleared just in time for the opening concert. Antony and the Johnsons performed with the Norwegian National Opera Orchestra on the roof of the new Opera House. It was the first-ever outdoor concert held at this glassy cubist structure on the water's edge of Oslofjord. Almost 9000 people spilled down the sloping roof to the stage, which was set up on a barge, the setting sun over Oslofjord behind it.

It was a stunning public setting for the private, aching song-poems of Antony Hegarty. He is a specialized acquired taste, with his round, androgynous face and soprano voice and spasmodic gestures and poses. His songs, over the course of a long Norwegian twilight, began to sound alike. The orchestra sighed and Antony moaned tunes with titles like "Kiss My Name" and then shyly curtsied. It was the warbling of Tiny Tim become symphonic and existential.

Unlike many European jazz festivals held in smaller towns, this one does not take over the city, because Oslo is large and cosmopolitan, with multiple competing summer events. For example, hordes of drunken Scotsmen in kilts, there for the World Cup qualification soccer match between Norway and Scotland, were a much more visible and audible presence on the streets of Oslo than the jazz festival. (Scotland got creamed 4-0, which rendered the men in kilts morose and, thankfully, quieter.) To find the jazz festival you had to search it out in 17 venues throughout the city center: jazz clubs, small bars, hotels, gray rock 'n roll dungeons, churches, restaurants—and that Opera House, whose full name is Den Norske Opera & Ballett. Despite the global recession and ticket prices that appeared high (at least to someone from a non-kroner economy), attendance at most concerts was excellent.

The jazz at this jazz festival started on day #2, at the Opera House, but this time inside, where the capacity is 1450. This horseshoe-shaped auditorium, opened in April 2008, has four levels of seating faced with beautiful dark-grained wood—Norwegian wood, presumably. An evening billed as "Til Radka" was quickly "utsolgt" (sold out), so a second performance was scheduled, and it too was utsolgt. The concerts were tributes to vocalist Radka Toneff, a revered figure in Norwegian jazz who committed suicide in 1982 at the age of 30. The band included several of the finest Norwegian players, some well-known outside Norway (Arild Andersen, Jon Christensen, Arve Henriksen, Karin Krog), some not (Per Jorgensen, Jon Eberson). Radka Toneff's signature song was Jimmy Webb's "The Moon's A Harsh Mistress." The band played a moody version with Jorgensen's muted trumpet at its core. For someone who has listened to Jon Christensen on ECM records for 30-or-so years, it was a kick to hear his precise, clean, suggestive cymbal work in person.

But at this concert dedicated to a singer, five vocalists predominated. Solveig Slettahjell's pure, alluring voice could not be more different from that of Tom Waits, which made her a perfect interpreter of his "Take It With Me." Karin Krog, Kirsten Braten Berg and Live Maria Roggen proved that they are true improvisers with jazz instruments for voices. The night ended with a strange, moving vocal performance by trumpeter Jørgensen. It was "Blame It On My Youth," a song that Radka Toneff never sang, but which perhaps alluded to her early death. After a rapt, hovering Arild Andersen bass solo, Jorgensen sang it falsetto, building it slowly from a whisper to a scream.

The most unique and utterly improbable project of the festival called itself Monk's Casino. A German quintet (pianist Alexander Von Schlippenbach, bass clarinetist Rudi Mahall, trumpeter Axel Dorner, bassist Jan Roder, drummer Uli Jenneseen) played the complete Monk canon—70 tunes—in three sets at the Nasjonal Jazzscene Victoria, on Oslo's main drag of Karl Johans Gate. Before you recognized one Monk tune, here came another, flying past your head. The spattering, careening solos by the two horns and Von Schlippenbach were necessarily concise. This quixotic, inspired jazz novelty act has been in existence for 13 years. There is a three-CD set on the Intakt label.