Originally Posted by
Brett A
I live in rural New England where it can be 90 degrees and 85 percent humidity for much of the summer. I've also toured extensively across the southwest including Death Valley and the rest of the Mojave desert in September when it's still 100+ degrees.
I used tight, white sun blocking arm and leg covers in the desert. I don't remember the brand. I bought them at REI. They're especially good if you get them wet first for evaporative cooling, But then the humidity in the desert is between 3 and 13 percent. They would probably just stay wet and uncomfortable back home with the humidity.
The rule of thumb in the desert is light, loose fitting clothing; basically wearing your own source of shade. In New England,,or in the southeast where you live, I'd try both sun sleeves and light, loose-fitting and see which is less uncomfortable. Both will diminish your body's ability to shed heat through sweating. But both are more comfortable than sunscreen IMO. I hate greasy stuff on my skin.
On the bike, I'm cooler in hot weather wearing skin-tight everything. We're water-cooled beings when it's hot, and water evaporates most quickly when it's exposed to moving air, hence tight, thin, wicking clothing. That said, my experience is in climates with humidity mostly under 70% in summer. It's my impression that stark white sunsleeves don't diminish the rate of sweat evaporation, plus being white means they don't absorb heat as much as your skin of whatever color. I don't like hot climbs with a tailwind, when the sweat off your nose lands on your top tube.