My venue is an amphitheatre. We have 7 water coolers scattered throughout the facility, and I always keep a water bottle where I can get to it easily. Typically, I refill that water bottle, 4 or 5 times a day, especially as we get into the warmer part of the year. I also wear a funny looking, wide brimmed hat, with a flap covering my neck, sunglasses, and sunscreen. The company provides the sunscreen. Even with all of this, I still get dehydrated and sunburned. Some days, between, the sun, the heat, and the physical exertion, I'm literally shaking at the end of the day from shear exhaustion. Fortunately, this is a very rare occurrence. It actually hasn't happened since I started wearing the funny looking hat.
Still, it would take a lot for me to trade what I do for an air conditioned "real" job.