Let’s be honest: On short runs in fair weather, you can run in just about anything. But if you plan to run more than a couple miles, and run in every season, the right apparel increases your comfort—and safety. 

Materials 101

Materials used in running-specific apparel aim to keep you dry and comfortable, both from your own sweat and from the elements. Some materials offer more durability than, say,  yoga-specific clothing. Some materials aim to ward off odor for days on end. And some recycled (and recyclable) materials actually help protect the environment. All fabrics fall into one of two categories: natural and synthetic, each with its pros and cons.

Synthetic

Baselayers, shirts, and pants in this category are typically made from nylon or polyester (nylon is more durable, while polyester is more breathable), often with some spandex for extra stretch. These materials are excellent at wicking sweat away from your skin and dry quickly. They’re also more durable than natural materials, and usually more affordable. On the downside, they’re made from petroleum. But more and more brands are using partially or completely recycled synthetic fibers. Synthetics also tend to get stinky quickly, but antimicrobial treatments are often applied to help keep garments fresh a little longer.

Natural

Merino wool is the most common fabric used in natural baselayers and shirts (bamboo, Tencel, and rayon fall under this category, too). Merino is comfortable (itchy wool is a relic of the past), great at regulating temperature, good at wicking, and naturally resists odors. But it wears down faster than synthetics, dries more slowly, and usually costs more. Some of the top-performing baselayers today are made with a blend of synthetic and merino fabrics, delivering the best of both worlds.   

TOPS

Do you expect full sun, full shade, or some combination of the two? Will you be climbing to higher elevations and cooler temperatures? Consider the conditions and forecast and then choose from these layers.

• Tank: In hot weather, airy tank-style tops made of technical fabrics will keep you coolest (though you’ll need sunscreen on your shoulders and upper arms). Tanks add versatility when layered under long- or even short-sleeved tees for variable conditions.
•  Tee: The most versatile top is a T-shirt made of technical fabric. They crossover to all four seasons and offer more sun protection than tanks.
•  Long-sleeve: Long-sleeve shirts are a staple for runners who are out all year long. Wear them alone on cool days, under midlayers or jackets on cold days, and over tanks or tees on variable days. 

OUTERWEAR

Runners need outerwear for two reasons: insulation and weather protection. For cold but dry conditions, you might need just a midlayer. For wet but mild weather, a rain shell might be all you want. Sometimes you just need wind protection. And sometimes you need more than one extra layer.    

• Midlayer: A midlayer can be as thin as a second long-sleeve shirt or as thick as a fleece or thin puffer jacket. It’s meant to be worn over your first layer for warmth in extreme cold.
• Vests: A lightweight vest made of wind-blocking material adds core warmth. Upside: A vest can add just a touch of critical insulation without causing you to overheat. Downside: Unless you’re running with a pack, vests can be difficult to carry when not needed, as they’re armless and can’t be tied around waists.
  
• Windshell: Windshells do just what the name implies: block wind. They’re generally made with a thin layer of nylon, and offer lightweight protection in a minimalist package. They’re not waterproof, but many have a DWR treatment that can shed light rain. 
  
• Rain shell: Rain shells, or “hardshells,” are constructed to keep you dry from rain, snow, sleet, and muck. Generally, rain shells are less breathable than windshells, though the best new rain shells breathe quite well. Rain shells for trail running don’t need excessive zippers or pockets (which add weight and bulk).

BOTTOMS

As with tops, weather plays a huge role in what you wear on your bottom half. But so does the type of terrain. Running on a trail overgrown with grass or branches that scratch your legs? Opt for longer bottoms. Rugged trail that has you butt-sliding down a rock face for a section? Choose the most durable materials.

•  Shorts: Trail and road running shorts can be interchangeable, though trail running-specific shorts tend to be cut longer for both style and protection. Trail running shorts also tend to have at least one zippered pocket for a car key, and other pockets for stashing gels and such. Shorts can be cut in loose-fitting shell material with an interior brief or without an interior brief, or they can be form-fitting “boy short”—or “bootie short”—style. Or shorts can have an outer shell and an inner boy short, which offer compression benefits and more coverage than an inner brief.
•  Skorts: The running “skort” combines an over-skirt made of lightweight technical material over boy shorts/bootie shorts—form-fitting shorts that extend down the thigh. Some runners prefer skorts to shorts because they can be cooler, and for style.
• Capris: Capris should be made of technical, sweat-wicking material. They extend past the knee to hit mid-calf, and can be great options for cool or variable weather. These are also known as three-quarter tights.
  
•  Tights: Form-fitting tights offer coverage and warmth. Tights come in various thicknesses and with varying ventilation properties and features, like perforations around the knees or zippered ankle cuffs. The warmest options have brushed liners for a cozy, insulating interior. 
•  Pants: Really, these are simply loose-fitting tights, and they offer similar warmth with a more casual feel. Running pants can snag on brush and branches more easily than tights, but might make a more comfortable post-run option for getting a drink or meal.