Protective clothing Minimize exposed skin with a light-colored, long-sleeve, collared shirt and lightweight pants. "You may feel warmer initially," says Death Valley National Park backcountry ranger Aaron Shandor, "but once you start moving, creating a breeze, and sweating, you’ll be much cooler."
Sun hat Best: A wide-brimmed sun hat (like Royal Robbins’s Extreme Expedition Hat; $20, royalrobbins.com). Cheaper: Tuck (or sew) a bandanna under the back rim of your cap, Lawrence of Arabia-style.
Skirt Women: Get maximum comfort and breathability in an above-the-knee cotton skirt, says Mountain Travel Sobek guide Shelli Ogilvy. And guys: Try Mountain Hardwear’s Mountain Kilt ($50, mountainhardwear.com).
Sleeping sack In jungle-worthy weather, pack a lightweight cotton model (such as Cocoon’s Cotton Mummyliner; $20, cocoon.at) instead of your sleeping bag. (And use it to line your bag for extra warmth in cold weather.)
Mist bottle Fill one at the trailhead and spritz yourself regularly on hot, dry hikes, advises Shandor.
Cotton shirt Yep, you read that right. Cotton’s slow-drying properties make it perfect for scorching temps: Soak a shirt in a stream, then put it on for sweet relief. "Warmth moves to a cooler area to equalize, so the cool water from a bandanna or T-shirt draws heat off your body," explains Iris Saxer, an instructor with the Wilderness Medicine Institute.
Portable shade Bring a backpacking umbrella for protection on the move or a light-colored tarp for lunchtime.
My Secret: Dennis Lewon
"Admittedly, there’s no science to back this up," says our executive editor, who once hiked through a Sonoran Desert heat wave. "But when I trek in temps above 100F, I like to drink a cup of hot tea in the afternoon in camp. Some say it makes you sweat more, which increases cooling. I think it slightly raises your internal body temperature, which makes the outside air feel cooler."