With the recent release of Fedora 25, the Fedora 26 release schedule is falling into place. The current Fedora 26 schedule projects a release date of July 4th, 2017. Fedora 26 Alpha is slated for release on April 4th, 2017 and Beta is aiming for June 6th, 2017.
These dates may change as development on Fedora 26 progresses, so always check the schedule for the most accurate version of the Fedora 26 schedule.
Updated: 2017 May 26