Every hiker should own a hooded sun shirt. The perfect layer, it can be worn next to skin or over a baselayer; it provides shade and warmth; and, best of all, it protects from light precip, breeze, and, of course, sunshine. But which one to get? This one. You will not find a more comfortable piece of clothing.
Softer than silk jammies (really), the maximum-protection UPF 50+ Crater Lake is made with an unremarkable 88/12 poly-elastane blend. So why so buttery? Its secret sauce is a 40-gauge knit—meaning that Mountain Hardwear packs in twice as many stitches per inch as your everyday T-shirt. The supertight knit is like a swimsuit—if your swimmie had no liner and fit like a flowy tunic. Beyond that, it’s all about the details: not-floppy hood, roomy-but-not-baggy fit, not-constricting thumbholes, and, for the women, a waist cinch and small zipper pocket on the right hip. After wearing the Crater Lake during a sun-drenched summer of hiking, climbing, wakeboarding, and trail running, we brought it to Catalonia. There, we got more rain than sun, but we still slid the Crater Lake under other layers and even wore it to bed. It’s luxurious enough to wear anytime, anywhere. (Women's version costs $60).