The album takes its name from the band's habit of starting their performance at 8:30 pm. At the time of the tour, the band were a four piece who would take the stage continuously for around two and a half hours, each of the members taking a solo spot to give not just a virtuoso performance, but to give the others a break. Wayne Shorter sometimes plays percussion instead of saxophone on stage, and on one of the studio tracks, the calypso inspired "Brown Street", Joe Zawinul's son Erich plays percussion along with Erskine and Pastorius.
The 8:30 tour saw Weather Report at the height of their commercial success, and the playlist leant heavily on the recent successes, "Black Market", "Birdland" and "Teen Town".
Jaco Pastorius played a notable solo, "Slang", which melded a multi-part bass solo using a rack-mounted MXR digital delay, leading into references to "Third Stone from the Sun" by Jimi Hendrix, "Portrait of Tracy" from his own solo work, then onto "(The Hills are Alive with) The Sound of Music". He finished off playing his bass with its own strap.
According to Peter Erskine, the band originally planned for the entire album to be live, but an engineer accidentally erased some of the material, prompting the band to go into the studio to record the fourth side.
The album was originally a double gatefold LP but the reissue on CD dropped a track, "Scarlet Woman", and was released as a single CD. In Japan, the album has been released as a 2-CD set with all the tracks of the original.