I spent four years in Arizona. I know of the heat.
In July and August...by noon...you are terribly miserable when you have to stand in the sun. Its around 106, and will coast to 110 around 3PM. By 6PM, it's starting to chill (in the heat sense)...getting back down to 102. By 8PM, it's around 99 degrees.
If you have a shade and plenty of liquids....you can probably sit there and get by for two hours easily. Without the shade and in direct sunlight...it'll start to make you hurt around 45 minutes into the experience.
I used to jog in July....on the base roads there at Tucson....at noon. I actually got to a point where I'd run two miles in twenty minutes...in the 106 degree heat. I'd come back to the gym and sip almost two glasses of water from the cooler....then go over to Burger King and buy two big ice teas (loaded with lemons and ice...the 100 ounce type). I trained myself to make it in the heat.
I read today, that the University of Arizona....next Wednesday...will have the President there, and the security folks are already making life miserable for the students and the parents who intend to be there. They want people to start to arrive at the stadium at 3PM....guests and graduates. Bachelor's degree folks, then master's degree folks. All "other" guests are supposed to be there by 4:30PM.
The president doesn't arrive until 7PM. So basically....its a four-hour spill...to get up to the start of his 30-minute speech.
Four hours in the May sun...with temperatures probably getting up around 100 by late afternoon. Parents and grandparents...sitting there in the sun...for possibly three hours....to survive this deal.
Heat stroke? Yep....I'll predict thirty to forty people already. Students in robes and surviving this deal for four hours? No....they'll remove the robes within an hour of this deal.
I feel sorry for these folks....and myself? I wouldn't sit there for four hours for my son (even if he were an Einstein and getting some degree). I'd shake his hand and thank him for his effort....and then find an air conditioned hotel room.