The official Yosemite page is declaring Tioga Pass open as of June 29th, the 3rd latest opening recorded by the NP.

This date was matched in 1983 as the joint 3rd latest Spring opening and the latest opening since 1995 when it opened on the 30th June. The latest opening recorded by officials at Yosemite was in 1998, opening on July 1st.

Dave.