Hard Shells Explained
Inexpensive, coated waterproof slickers are the best protection from a deluge—pretty much perfect if you are standing around watching a soccer game or fishing in cold, wet conditions. But on warmer days or any time you're engaged in activities where you exert yourself, you want protection that's not only waterproof but also breathable. We'll save the science for the real gear geeks, but the basic concept dictates that the fabric is dense enough to prevent moisture penetration on the outside (read: keeping you dry), while at the same time, allow sweat to evaporate (read: keep you from overheating; the breathable part of the equation). And in all but the hottest conditions when you're gonna sweat no matter what, the concept is sound. Pair a hard shell with a wicking base or mid-layer, and any sweat that you may emit will be pulled to the outer layers of the clothing and then evaporate through the breathable layer of the hard shell.
What to Look For
Everyone knows the Gore-Tex name... but this is merely one type of hard shell waterproof/breathable fabric (which is further parsed, in ascending order of durability, into Gore-Tex Paclite, Performance Shell, and Pro Shell). REI and other brands like Westcomb use eVent, which some consider to be more breathable than Gore Tex, while most manufacturers use both Gore-Tex and also deploy their own proprietary waterproof/breathable laminates, from Patagonia's tried-n-true Deluge DWR (durable water repellent) to Mountain Hardwear's new Dry.Q fabric.
For truly bombproof clothes, make sure the piece has sealed seams, or there will be leakage. Same goes for waterproof zips (if a jacket doesn't have 'em, be sure there's a flap over the zipper to prevent water from penetrating through the zipper teeth). And before you shell out the $$ for these often-pricy products, consider your uses. The traditional shell offers protection from the elements but not insulation, and are typically sized to accommodate a few layers underneath—and thus can be used in a range of conditions from warm to cold weather. But if you clock hours in cold weather, consider insulated items that are often all-in-one package of warmth and rain protection, pairing the waterproof/breathable components with fleece, wool, or down insulation.
When it comes to pants, we heartily recommend venting zippers, which typically run down either the inner thighs or along the outer pants seams. This will help you dump heat in high-aerobic activities, but then seal things up when stuff gets really wet or you start to get cold (as in sitting on a ski lift or reaching base camp). For truly cold weather venting is less of an issue.
Venting zips on jackets are found more on non-insulate jackets, usually under the arms. Again, for highly aerobic activities, vents are great. But for sports where weight is a consideration (mountaineering, backpacking), you won't find pit zips, as well as othermany bells and whistles based on the theory that if you're moving lighter, you'll exert less and therefore have less heat to expel.
Details mentioned in this article were accurate at the time of publication