I was told by a CM that hours for Aug. will be posted May 1, but I doubt it!
At the top of Disboards page you will find a selection "Park Hours, Fireworks, Parades." Click there and type in your dates for the projected hours based upon last year's hours.
Fantasmic! is usually right at Studios closing, IllumiNations is always at 9PM, Wishes usually at closing, and last year Spectro only ran Sat. night in late August, 1 hour before closing.
I'm frustrated with how difficult is is to plan without actual hours, but we just have to be flexible.
These late-August hours are significantly shorter compared to the rest of the summer indicating lower park attendance.