This is not meant to scare people, but to advise proper caution.
An 11-year-old boy has died after he and his mom were stranded on a DV trip. These folks were from Las Vegas, where they were accustomed to hot dry weather but probably spent most of their summer days in a/c facilities.
I can think of several things that might have saved this family. I'll come back later and elaborate, but just wanted to get this on the forum.
This does not mean you should cancel your DV plans. As many of us have consistently said, people go there in the hottest weather and do fine, survive, even have a good time. Read the threads about hot weather survival and then make an informed choice.