Your season pass is good for those operating days which were announced when you bought your pass. That means daily May 13-September 4, and September 9, 10, 16, 17, 22-24, 29-30, October 1, 6-8, and 13-15. If it is good on any other days, that's a bonus. If the park adds operating days other than those promised with the pass, they are under no obligation to accept the pass for those days.
(Dave glances at the calendar)
Hey! No September buy-out this year???
--Dave Althoff, Jr.