The Wii U version of Watch Dogs has suffered several delays so far, with Ubisoft justifying that the delay was necessary in order to focus on the platforms with the "broadest possible benefit." The delay might be longer than most would expect, with the Wii U version of the title only being available this Autumn, according to Uplay.
The now-removed listing on Ubisoft's North American web store (which can be seen below), states that the title will be available on Wii U this Fall. In addition, a US Ubisoft representative has told Nintendo Enthusiast that this release window is indeed true, which means that the title will launch on Wii U at least 4 months after its release on the remaining consoles.
Although Ubisoft has yet to officially announce the release date, this is first release window we have had since the Wii U version's first delay. Watch Dogs will be available on the 27th of May on PS4, Xbox One, PS3, Xbox 360, and PC.
Source: Nintendo Enthusiast