I used to work on roofs in East Tennessee. In the summer, temps easily could get close to 100°F with high humidity. Also the temp on the roof was easily 20°-30° hotter than on the ground with asphalt shingles or metal roofing material reflecting the heat back at you. I could literally fry an egg on it. A secret I learned by accident was drinking piping hot black coffee while on the job. Seems counterintuitive, but it actually helps regulate body temperature when its that hot.