A few years back I did a bunch of work with an outdoor
theatre in Fort Worth. 100 degrees here isn't uncommon (in fact, today saw upwards of 100, I believe), even before the heat index is calculated. We all learned that water is a must. Or liquids of some sort. And that it's much easier to minimize the amount of in-the-sun-without-shade work you do in the heat of the day if you work more in the evening and morning.
The space was rather well shaded, quite a few old trees, and there were a few buildings on the property too, so every so often we'd take breaks in the shade or air conditioning or make a store run or something of the sort that would get us out of the sun.
For a fair bit of the season we also inherited a pet spider in the booth; he made his home right by the door. Harmless thing, thankfully. Fun stuff.