Aether/Primal Data Centers: Monday, May 15, 2017 12:00 a.m. to Wednesday, May 17, 2017 12:00 a.m. (PDT)
Elemental / Gaia / Mana / Chaos Data centers:
Tuesday, May 16, 2017 12:00 a.m. to Wednesday, May 17, 2017 12:00 a.m. (PDT)

Aether and Primal having an extra day is likely because of how heavily populated those two data centers are.

We'll all be compensated with 1 extra sub day.