In a few instances I will leave behind my rain gear, notably short backpacking trips in dry environments when there is no precipitation in the forecast, and longer trips in hot and humid environments when a soaking is actually welcomed. But otherwise I bring something to help keep me dry when it rains.
A rain jacket and rain pants are Items 10 & 11 of the Core 13, my collection of essential backpacking clothing that can be mixed-and-matched to create appropriate systems for any set of 3-season conditions.
When hiking in the rain, the usual attire is a rain jacket and rain pants. But before I cover these product types in greater detail, two other options deserve mention:
- Umbrellas, and
These rain defenses do one thing right: They allow for excellent airflow, which helps to keep the user relatively cool (via convection) and dry (via evaporation of perspiration).
Otherwise, however, they are a tough sell. An umbrella is useless in high winds or when bushwhacking, snags when on poorly maintained trails, takes out of commission a hand and arm, and creates noticeable drag. A poncho also struggles in high winds or when off-trail, but more importantly it leaves exposed the lower arms and legs, a major liability in cooler conditions.
I would additionally add that, probably due to limited consumer interest, there is little innovation in the umbrella and poncho space, thus curbing interest further. An unbreakable umbrella with a carbon fiber shaft and cuben fiber canopy? Sorry, it does not exist. A poncho with an excellently designed hood and full arm protection? Keep dreaming.
Waterproof-breathable rain gear
A rain jacket and pants are much more field-friendly than an umbrella or poncho. However, their form-fitting silhouettes create a problem: near complete loss of airflow.
If they were to be made of the same waterproof fabric used in umbrella canopies, ponchos, tarps, and tent flies — e.g. polyurethane-coated nylon, silicone-impregnated nylon, or cuben fiber — the wearer would have an effective protection against external precipitation, but they would bathe in their perspiration that becomes trapped in the garment during aerobic activity. (For low-aerobic activity, however, fully waterproof rain gear is great. Next time you watch a baseball game or go fishing in the rain, bring along something like the Helly Hensen Lerwick Rain Jacket.)
The outdoor industry’s solution to this body bag scenario have been waterproof-breathable fabrics (WP/B), e.g. Gore-Tex, eVent, NeoShell, plus proprietary fabrics like Marmot’s Precip and Patagonia’s H2No. That “waterproof-breathable” is an oxymoron is perhaps the first clue that this fabric technology might be overhyped. Think: A “waterproof” fabric does not allow moisture through it, yet a “breathable” fabric does — So how can a material be both?
Why waterproof-breathable fabrics fail
In my experience, waterproof-breathable fabrics are neither waterproof nor breathable, especially during extended use and/or if the garment is not brand new. While there are measurable performance differences between the degrees of water-resistance and breathability of different fabrics, the ultimate outcome is the same: I will get wet from the outside, the inside, or both. It’s really just a question of timing and method.
Outside. The Achilles heel of WP/B fabrics is the durable water repellent (DWR) treatment applied to the face fabric. This long-chain (C8) fluorocarbon-based treatment easily degrades due to abrasion and contaminants (e.g. dirt, body oils, sunscreen), which causes the face fabric to become saturated with moisture. Since it is more humid outside the jacket than inside it, moisture is “pulled” through the jacket by the drier air inside. With new restrictions C8 soon taking effect, the lackluster performance of DWR will decline further.
The DWR finish can be restored with wash-in and spray-on treatments like Nikwax TX Direct Wash In. They definitely help, but I have found that the DWR is never as-good-as-new again. And without a functional DWR, wet-out is inevitable.
Inside. Technically, waterproof/breathable fabrics are breathable — i.e. moisture can transmit through the fabric, via solid state diffusion or direct venting. But so too is a jacket made of trash bag material with a few pinholes in it. Regardless of marketing claims to the contrary, the breathability of WP/B fabrics is utterly inadequate relative to a normal rate of perspiration when hiking, especially in warm and/or humid conditions. So even if you managed to stay dry on the outside while wearing WP/B clothing (like if it’s a sunny day) you will get wet from the inside due to trapped perspiration.
Fit and features
Proper 3-season rain shells should be sized to fit over a hiking shirt and mid-layer top, or pants and underwear. Unlike winter shells, they need not be so large to fit over an insulated jacket or pants.
Many high-end technical rain jackets such as the Arc’teryx Beta LT Jacket are “helmet-compatible,” which sounds sexy but which for hat-wearing backpackers results an excessively large and poor-fitting hood.
Pockets, if any, need to be accessible while wearing a backpack — otherwise, why bother? A kangaroo-pouch protected with a waterproof flap would be superb, but most jackets feature smaller, marginally useful pockets with vertical or diagonal zippers.
10. My picks and suggestions
When choosing rain gear for a particular trip, I mostly account for the:
- Likelihood and duration of rain events;
- Relative humidity; and,
- Ambient temperature.
If I expect no or little precipitation, short-lived storms, low humidity, and cool temperatures, I pack ultralight and relatively inexpensive rain gear like the Outdoor Research Helium II Jacket or the Marmot Precip Jacket, plus perhaps the matching Helium Pants or Essence Pants for full-body defense against cold-and-wet conditions. These garments will have minimal features: no pit zips, ankle zips, multiple hood adjustments, hem closure, or pockets.
My rationale for these choices is simple. First, since I may not even need my rain gear, I’d like to keep down its weight and volume. Second, if I do need it, by the time I’m starting to get wet (from the outside or inside), the storm will have hopefully passed through. Of course, sometimes they don’t do so quickly, but that’s a risk I’m willing to take.
When expected conditions are at the other end of the spectrum — reliable and long-lasting rain events, high humidity, and/or warm temperatures — WP/B fabrics really struggle. In these conditions, I think rain gear with generous venting and air flow will be far more effective in keeping you dry than rain gear with a best-in-class WP/B fabric.
Traditionally, venting features have stopped at pit zips. Realizing that this is grossly inadequate, I’m excited to see companies doing more. The Outdoor Research Foray Jacket, for instance, features a two-way front zipper and side zippers running from the waist hem to the armpit. (Too bad the product video was shot in Joshua Tree National Park — it’s hard to trust someone talking about rain gear while surrounded by cactus and desert shrubbery.)
Sierra Designs has taken ventilation another step further with its Elite Cagoule Jacket and Elite Rain Chaps, new for Spring 2015. I used a prototype last summer but not enough for review, and I don’t yet have production pieces. At worst, Sierra Designs gets credit for designing unconventional but poor-performing rain gear. At best, the Cagoule and Chaps are the start of an evolution in rain gear, in which we will see more emphasis placed on ventilation than fabric breathability.
If you have given up on shell jacket and pants in wet, warm, and humid conditions, I would certainly understand. As alternatives, consider the Outdoor Products Packframe Poncho or the REI Travel Umbrella.