In summers during my undergraduate days, I worked at a gold mine in the desert of California (next valley west of Death Valley). There was one guy there who had been working in the desert (previously in Yuma, AZ) for many years and always wore a long sleeve sweatshirt (Long pants were mandatory for safety reasons). When I was told why he did it (the argument above, about not exposing skin to the sun to minimize water loss), I accepted his argument as correct. This did not lead to my wearing long sleeves, however. Somewhere in my mind the idea that I would feel like I was being baked overrode my acceptance of his reasoning. I didn't even test the idea. Some "instinct" like thought told me it was wrong.