Jeans and Cotton T's will overheat you! I cant imagine wearing jeans all day! Poly work pants are less weight. I prefer shorts for myself. Some of my guys prefer pants. We all prefer a moisture wicking shirt. Makes all the difference in the world! 20# of ice per day per truck to keep the water cold! Hydrate everytime you come back to the truck or change equipment!
BTW.........I hope you are wearing a big hat! 15 degrees difference alone with a good hat!