When a rain jacket is said to be waterproof and breathable, what does that mean? Waterproof fabric blocks out normal rain and drizzle, so that’s easy enough to understand. Breathability, on the other hand, is the extent to which the fabric allows vapor to escape. Why is this important? Try running while wearing a garbage bag. It might keep the rain out, but you’ll be absolutely drenched in your own sweat. The perspiration vapors have nowhere to go. So, depending on your activity level, breathability is as crucial to staying dry as whether or not your rain jacket is waterproof.
Gore-Tex is the most well known of the waterproof/breathable technologies. Other technologies include System Three, used in some of our Eastern Mountain Sports jackets; PreCip and MemBrain by Marmot; and HyVent, developed by The North Face.
2-Layer, 2.5-Layer, and 3-Layer Waterproof/Breathable Rain Jackets
When you read a jacket description that talks about 2-layer Gore-Tex or 3-layer HyVent, it’s referring to the type of lining used to protect the waterproof/breathable technology. Left on their own, waterproof/breathable laminates and membranes are vulnerable to abrasion, so some sort of protective lining is required.
2-layer is the most common kind of waterproof/breathable construction. The laminate or membrane is applied to the face fabric, with nothing attached on the interior—hence, the 2-layer. A loose hanging layer is used to provide protection. This option tends to be less expensive, but adds a little weight to the jacket.
2.5-layer construction features the laminate or membrane applied to the face fabric, just like the 2-layer. However, on the inside of the jacket a series of laminated “dots” or a laminated grid pattern is used to provide a degree of abrasion resistance. 2.5-layer waterproof breathable jackets are ultralight and very packable.
3-layer jackets are the most expensive option, but are fairly light and extremely durable. Like the other construction methods, the waterproof/breathable laminate or membrane is applied to the outer shell fabric. On the inside, however, a liner fabric is applied directly, creating a sort-of 3-layer sandwich.
Types of Venting
Venting helps you stay cool when needed. It also aids breathability. When the jacket’s front zipper is opened, for example, water vapor (perspiration) is easily allowed to escape.
Pit zips are often featured in non-insulated shell jackets. These underarm zippers let excess heat escape when opened. It’s a convenient way to regulate your temperature when you’re hiking, skiing, or working up a sweat. Similar to pit zips, core vents are located on the sides of the jacket and allow a small degree of airflow.
Usually backed up with a mesh panel, a jacket’s back vent is another effective way to stay cool. However, this is only a warm-weather option, as the vent can’t be totally closed.
Rain Jackets for Hiking and Backpacking
When hiking hard or hauling a heavy pack, you’ll undoubtedly be working up a sweat, so go with a jacket that has a full front zipper for optimal venting as well as underarm pit zips.
Non-insulated Jackets for Skiing, Snowshoeing, and Winter Sports
A rain jacket, if it’s durable and provides proper venting, can be used year-round, even in cold weather. Make sure the jacket is roomy enough to accommodate multiple layers underneath, including a fleece sweater or two. For venting, choose a non-insulated jacket with pit zips and a full zippered front. 2- or 3-layer construction is preferable.
Rain Jackets for Climbing
Climbing shells should be lightweight and durable. 3-layer construction works best. Also opt for pit zips, a full-zip front, and a full hood, ideally one that’s removable.
Rain Jackets for Running
Many runners opt for the improved breathability of a soft shell jacket. If you do choose a waterproof rain jacket, get one with maximum ventilation. Pit zips, full front zipper, maybe even a back vent. Get a hoodless jacket or one with a removable hood. 2.5-layer construction is best, as it’s the lightest waterproof/breathable option available.
Soft shell fabric is water resistant (not waterproof), wind resistant, and often offers good stretch and mobility. Jackets made of soft shell are ideal for climbing, running, and cross-country skiing. These jackets usually feature a trim athletic fit.
You can usually tell a traditional “hard shell” rain jacket from a soft shell jacket by the outer texture. Standard rain jackets are smooth and shiny, whereas a soft shell feels more like a tightly woven sweatshirt.
Understanding Water Resistance
Designed to block out a drizzle or even a light rain, water-resistant soft shell jackets are exceptionally breathable and usually less expensive than waterproof/breathable outerwear (remember—breathability lets water vapors escape). Someone who’s adventure racing or running in the rain might perspire at a greater rate than a waterproof/breathable jacket can handle, and would probably be better off with a water-resistant jacket.
Soft Shell Warmth
Soft shell jackets come in different thicknesses. Those designed for spring/summer/fall are lightweight and offer only minimal insulation—enough to take the edge off a chilly morning. Winter soft shells are usually lined with a thin polyester fleece layer, making them warmer, but not quite as stretchable.
Uses of Soft Shell Jackets
Because of their weather resistance and excellent mobility, soft shell jackets are an ideal choice for highly aerobic sports such as ice climbing, rock climbing, snowshoeing, Nordic skiing, running, and cold-weather biking.
Fill Power—The 3D structure of down clusters creates "loft" that traps air. The greater the loft, the warmer the insulation. "Fill power" is a measurement of that loft. This is accomplished by measuring how many cubic inches an ounce of down displaces when allowed to expand to its fullest. If an ounce of down takes up 500 cubic inches of space, then it has a 500 fill power; 700 cubic inches equals 700 fill power; and so on.
Sources of Down—Geese and ducks are the major sources of down insulation. Goose down is loftier (higher fill power) than duck down, but also more expensive. Goose down is the preferred choice for people looking for lightweight products. Eastern European goose down is known for its extremely large down clusters that create very high loft, sometimes as much as 800 fill.
Compressibility—Compared to synthetic insulations, down is typically more compressible, meaning that it can be packed into a very small space. This is great if you need to stow your down jacket or sleeping bag in a backpack.
Warmth-to-Weight Ratio—Ounce for ounce, goose down is warmer than most synthetic insulations.
Longevity—Down is very resilient and will retain its loft and ability to insulate for many years if you care for it properly. Of all the reasons to choose down, this might be the strongest one.
Poor Performance When Wet—Down provides zero insulation when wet. Having said that, the natural oils in goose down do provide some water resistance. After all, geese and ducks swim in near-freezing water all the time, and they’re fine. Also, the water-resistant shell fabric of most down jackets will block out snow (you will likely be wearing only a down jacket when the temperature is below freezing).
Generally, synthetic insulation performs better than down in wet weather. However, compared to down, synthetics are not quite as compressible and don’t have as long a life span.
PrimaLoft is the most common synthetic insulation in use. It’s extremely hydrophobic, meaning that it’s extremely hard to get the fibers wet. If you’re skiing or mountaineering deep in the backcountry where you can’t afford to have wet insulation, PrimaLoft is an excellent choice. Also, compared to other synthetics, PrimaLoft is very lightweight and compressible.
A 3-in-1 jacket is composed of a shell and a removable insulated liner. It’s called 3-in-1 because you can wear just the shell, just the insulated liner, or both attached together. Obviously, this is a very flexible system that can be worn in a number of different activities.
Fleece is a soft-napped synthetic fabric (usually polyester) that’s warm, exceptionally soft, quick drying, and lightweight. First created as “Polarfleece” by Malden Mills (now Polartec, LLC), fleece quickly became the insulating fabric of choice for skiing, snowshoeing, climbing, and winter mountaineering. In fact, Polarfleece was recognized by Time magazine as one of the 100 most important inventions of the 20th century.
Fleece is an outstanding insulator for its relatively low bulk. Typically, fleece comes in a variety of thicknesses/weights: micro, 100, 200, and 300, with 300 being the heaviest. In a traditional layering system, a fleece sweater or jacket is worn as a midlayer, with a very thin base layer worn underneath against the skin, and a weatherproof non-insulated shell jacket worn on the outside.
Fleece is very hydrophobic, holding less than 1% of its weight in water. Instead, moisture passes through the fabric (wicking), where it can soak into an outer layer or spread out and evaporate once it’s exposed to air. This means that a fleece jacket won’t get waterlogged, will dry quickly, and will insulate even if wet.
Standard fleece doesn’t block out the wind; it’s very breathable, which adds to your comfort if you’re hiking, skiing, or climbing hard. But on a windy day, normal fleece should be worn only under a shell jacket.
The exception is wind-blocking fleece. This fleece is specifically designed to resist the wind and can be used as an outer layer, much the same way as soft shells are worn.
Keep in mind that not all fleece is equal. There’s a huge difference in durability, warmth, and softness between high-quality fleece and cheap imitations. Polartec, for example, remains the gold standard of high-performance fleece and can be depended on to maintain its soft texture and resist pilling through multiple washings.
Fleece Jackets for Skiing
Downhill skiing involves quite a bit of sitting around on exposed chair lifts, interrupted by brief runs downhill. Opt for heavy insulation here—200 (midweight) or 300 (heavyweight) fleece is best. In most conditions you’ll want to wear a waterproof/breathable shell over the insulating layer, so don’t worry about the fleece being windproof.
Fleece Jackets for Nordic Skiing
Cross-country skiing is a highly aerobic activity that keeps your body cranking out the heat. Usually, not as much insulation is required. Often a micro or 100 (lightweight) fleece will suffice. If it’s not snowing, a wind-resistant fleece can be worn as an outer layer.
Fleece Jackets for Winter Mountaineering
Pack extra insulation in the backcountry. Be prepared to wear multiple midlayers, like a 100 combined with a 200, or even with a 300.
For everyday use, it’s best to keep a wide variety of fleece in your closet. If it’s really cold, opt for a 300, or if it’s mild out, then wear a 100—and so forth.