Six Flags has altered the operation schedules for March, adding hours on March 19 & 20th. Previously the park was not scheduled to be open on these days. Hours are from 10:30AM-7:00PM on both days. These changes have been reflected in our online schedule.
Full Six Flags' press release is available here
Join Six Flags Fiesta Texas for more thrilling fun and excitement as the park will open additionally Thursday, March 19 and Friday, March 20 from 10:30 a.m.
to 7 p.m. adding to the already longest season in our history!
It was not mentioned in the press release, but the schedule was altered to make March 11 & March 13 as closed days, where the park was previously open on these days. I am not sure if these changes were official as the press release came out 3/11/09... however they were removed on the Six Flags operational calendar (per the official SF website).