On the Extra Magic Hours page it list them as “Morning” or “Evening” Extra Magic Hours and what attractions will be open during Extra Magic Hours.
How it all works:
[I] Extra Magic Hours
Each day one of the Disney Theme Parks opens an hour early or stays open up to three hours after regular Park closing, so Disney Resort Guests* can enjoy easy access to select attractions — even the most popular ones! With Extra Magic Hours, you can make the most of your vacation time and see and do everything at an easy, relaxed pace.
If you want to take advantage of this benefit and have a Magic Your Way Base Ticket, your Theme Park selection must be the Park offering the Extra Magic Hours benefit that day. Remember, you can only visit one Theme Park per day with the Magic Your Way Base Ticket. To get the most out of the Extra Magic Hours benefit, just add the Park Hopper® Option to your ticket. Then you can go from Theme Park to Theme Park on the same day, including whichever Park has Extra Magic Hours.
To take advantage of Extra Magic Hours at the Water Parks, you must have a Resort I.D.