Not early enough! Haha, there is a lot of frustration over their timeliness for releasing stuff like that. Usually it isn't until 30 days out that you get anything, and even then they are filling in and changing things sometimes.
You will usually be able to make your dining reservations at 60 days out, and the park hours will probably not be published yet.
A lot of planners look at their historical operating hours from years past and use those to predict what the hours will most likely be set at.
Have fun planning!