and it is hot and humid but we pace ourselves.. We go early morning and really see a lot before the crowds and the heat hit..
Also, remember that AK is a very hot park and not too many places to cool off. We usually go in the am and then leave and return later in the day. Epcot is great for mid afternoon because there is A/C places to get out of the sun.
Also because the parks are open long, we do the eaarly morning and then hop to another park to cool off or go back the OKW for a swim and then go back to the parks when it is cooler later in the day.
Planning will make the visit wonderful... because standing in lines for an hour in the hot mid day sun is not fun for anyone.. Bring lots of water bottles, hats and sunscreen.