Every year in Vitoria-Gasteiz, there is great Jazz festival around the days of San Fermín. This year it goes from July 17th till the 21st. It is just one our away from Pamplona, on a very confortable freeway. If you like jazz music and you have some time, I recomend you to visit this amazing city. Vitoria really has a lot of history, a must see is the Gothic Cathedral that it is under reconstruction, and you can visit the work in progress, it is amazing. And food, as part of the Basque Country, is another great issue there, you will find some very fine restaurants. By thge way, Vitoria is the greenest city in Spain, so you can also enjoy their gardens.
I found this great article from las year, publised at the Guardian, talking about all the jazz festivals that take place in Europe in the summer time and Vitoria is one of them. This year is going to be even better. Carla Bruni (France´s ex first lady) with her chic and soft voice. Also, the historical Kool and the gang will play as well as the Mingus big band. It is going to be 5 amazing days full of jazz, or I should say JAZZ.
You can check all the info about this years concerts at the official web site of the festival jazzvitoria.com