Wonderful Day (previously known as It’s A Wonderful Day) is a song recorded late January 1986 at Sunset Sound in Hollywood, California. The title was likely inspired by a quote from a scene that was cut from Under The Cherry Moon, where Prince says 'It’s a Wonderful Day' to a Venus de Milo statue. He was working on scoring the scene in the days prior to this session.
The song was initially included as the third track on the late April 1986 configuration of Dream Factory, and was kept as the third track on the 3 June 1986 configuration, but was replaced by Train on the 18 July 1986 configuration. Engineer Susan Rogers has stated that Prince may have always planned on replacing the track before release, and used it as a placeholder to find a track with a similar feel.
An instrumental portion of the track was included as background music in the Under The Cherry Moon movie, in a scene where Tricky and Christopher Tracy are arguing (See Under The Cherry Moon cues for details). The full version remains unreleased, however.
In September 2020, both the edit that was on the early of Dream Factory configurations and an extended version of song were released on two of the discs with previously unreleased tracks included with the Sign O’ The Times Super Deluxe Edition (Prince’s Original version as the fifth track of Vault Tracks part 1 and the 12" Mix as the twelfth track of Vault Tracks part 3).