A June projection is incredibly unlikely.
I acknowledge that history may hint.
Here are the three major revisions of the Macbook Pro according to wiki
January 10, 2006; 9 years ago (original release)
October 14, 2008 (unibody release)
June 11, 2012 (unibody with retina display release)
https://en.wikipedia.org/wiki/MacBook_Pro
The rMBP looks old now. It's time for a reboot. Still can't see a Skylake successor to Haswell or Broadwell released by Intel with the same capabilities as the integrated graphics processor, the Iris Pro, available now.
https://www.macrumors.com/2015/09/02/intel-skylake-notebooks-desktops/
The buyers guide combine release cycles for both the 13" and 15" which by history we know have had different dates of announcement. It isn't a fair way to calculate an average release cycle. From 2012 to 2015, there have also been 3 mid year releases.
Impatience