May 26 (Bloomberg) -- Jazz festivals have come to be as much a part of the European summer as flight delays and fake city beaches. Old ones continue, new ones arrive, and they all just get bigger and bigger. Here are some to watch out for.

June 26-July 6: JAZZ ASCONA, NEW ORLEANS & CLASSICS. Featuring the likes of Duffy Jackson, Scott Hamilton, the Vache Brothers, and the Hot Club of Aussies, this festival's specialty is traditional jazz, from New Orleans to Chicago. Ascona is in Ticino, a kind of paradise on earth, with Swiss efficiency and Italian food.

June 27-July 11: JAZZ A VIENNE. The 7,000-place Roman amphitheatre in Vienne, France is stunning. The acoustics are wonderful, and looking down on the performers changes things. Ornette Coleman, Diana Krall, Buddy Guy, Sonny Rollins and more.

July 2-16: ISTANBUL INTERNATIONAL JAZZ FESTIVAL This is enough off the beaten track to make it special. The concerts are in theaters around town. Carla Bley, Nnenna Freelon, Herbie Hancock, Paulo Fresu, plus some astonishing Turkish musicians.

July 4-13: ALLGARVE JAZZ: On the other end of Europe, Portugal's Algarve is best known for its beaches, golf courses and seafood. Manhattan Transfer, Dee Dee Bridgewater, Lucky Peterson and more.

July 4-19: MONTREUX JAZZ FESTIVAL. Montreux was the first major pop festival to masquerade as a jazz festival. So what, you might ask, is the big deal? Well, everybody wants to latch on to the coattails of the most creative music of our times. Leonard Cohen, Alicia Keys, Gnarls Barkley, Joan Baez, and Quincy Jones's 75th birthday celebration at the Stravinsky Auditorium.

July 11-13: NORTH SEA JAZZ FESTIVAL. A gigantic affair in Rotterdam, Netherlands, squeezed into three days, with simultaneous concerts by the likes of Bobby McFerrin, Gary Burton, Pat Metheny, Charles Lloyd, Maria Schneider, and Diana Krall, who compete with the real subject of this festival: beer.

July 11-20: JAZZ A JUAN. A cultural diversion in Antibes-Juan Les Pins, France, for anyone crazy enough to be on the Cote d'Azur in July. Keith Jarrett Trio and more.

July 11-20: UMBRIA JAZZ. The same Americans play in these monster festivals so that the producers can amortize the transatlantic plane fares. But the music is good and they seem to make money for all concerned, so let's not quibble. This is the 35th Umbria Festival, in Perugia, Italy. Sonny Rollins, Enrico Rava, Stefano Bollani, Herbie Hancock, Alicia Keys, and more and more.

July 12-20: PORI INTERNATIONAL JAZZ FESTIVAL. Carlos Santana, Amina Claudine Myers and their like in the Kirjurinhoto park arena in Pori, Finland, and in converted loft and factory spaces in the rehabilitated docklands along the river.

July 22-27: HEINEKEN JAZZALDIA. Musicians such as Kenny Barron and Jean-Luc Ponty play between the restored buildings of the lovely old town of San Sebastian in Spain.

Aug. 1-17: JAZZ IN MARCIAC. Wynton Marsalis, who wrote the ``Marciac Suite,'' presides here and this otherwise modest small town in southwestern France shines brightly during this festival, known familiarly as JIM.