The purpose of the shell is to protect you from environmental conditions. Finding the right shell is quite challenging because staying dry and comfortable requires managing external moisture from rain, sleet, and snow as well as managing internally generated moisture from perspiration and sweat. There is no perfect / magic material that does all this in all conditions. As a result, learning good techniques to manage moisture in sustained rain is as important as selecting the right rain gear.
Most rain gear is not only waterproof, but is also windproof and has some insulating characteristics. In warmer weather this is a serious problem because the wearer will often over heat, start sweating, and then find themselves almost as damp as if they were walking around in the rain without protection. Greater air permeability is typically a good predictor of rain gear comfort.
I something hear people rave about the breathability of a garment that both laboratory tests and my personal experience suggestion are at best mediocre like the original Marmot Precip. I think this is often because the person raving about breathability has not used the garment doing heavy work in challenging conditions and/or is comparing the garment to a non-breathability alternative.
There is nothing which satisfies me 100% of the time. If the temperature is more than 60F and I am active, I typically don’t bother with rain gear and just get wet. When engaged in casual activities I might use an umbrella. When it’s cooler and I am engaged in high energy activities I will either use a ArcTeryx Norvan SL (review) rain jacket or just get wet wearing a Patagonia Thermal Weight Capilene base with, or without a wind shirt. I have used a Columbia Outdry Featherweight Shell Jacket a bit this year with more testing this winter. It is reportable to be immune from wet out like the Norvan SL. I have found it moderately breathable (doesn’t match eVENT DVT or Gore Shakedry), and is suppose to be durable enough for use backpacking. I typically just let my legs get wet. When the temperature is below 45F and I am not running or cycling I sometimes use a pair of Zpacks Vertice Rain Pants.
Types of Rain Protection
There are a variety of approaches people take:
- Jackets/Pants: Most common approach and what I normally recommend. Typically made from some sort of waterproof material, though there is a growing number of people who use materials that are not fully waterproof in a system to keep the wearer’s micro climate comfortable even if they aren’t 100% dry. Most of this post will be about jackets.
- The Packa: has elements of a pack cover and a rain jacket with sleeves, a front zipper, and pit-zips for ventilation. While it looks a bit like a poncho, I found it significantly more protective in heavy wind and rain. The pit zips provides much better control of side ventilation while the arms were were significantly better protection, especially when using trekking poles.
- Poncho: have good ventilation and can are be very light weight. Many people like that a poncho can be put on without removing a backpack, there by performing triple duty: rain gear, pack cover and later shelter. Some ultra light backpackers use ponchos made from sil-nylon, spinnaker cloth, or cuben such as the MLD Pro Poncho or Sgt Rock hammock friendly poncho/tarp. Elsewhere I have written a bit about using a poncho as a shelter. The cheapest are typically fragile “emergency” ponchos made from plastic is weight just a couple of ounces. These can be effective in moderate conditions, but they are very easy to tear. Finally, there are vinyl / PVC ponchos which can typically be found as hardware stores. These ponchos are inexpensive and typically weight 8-16oz. They are durable enough to wear, but I won’t recommend using them as a shelter. Disadvantages of using a poncho are that many people find them ineffective in high winds, awkward when bushwhacking and impossible to use when climbing. My personal experience is that my chest get soaked in sweat from condensation and my sides get damp from wind blown rain. I have tried ponchos three 6 month or longer periods. After each poncho experiment I switched back to a rain jacket. There are finally a few companies making ponchos from a waterproof breathable material like DriDucks Poncho. I have experimented with the DriDucks poncho and found my chest was no longer getting soaked. Still, I generally prefer rain jackets.
- Umbrella: Some people like to use wind/water resistant jackets + umbrellas. Certainly very good ventilation. Strong winds or going off trail can pose significantly challenges to the use of umbrellas. Some people have found ways to mount an umbrella on their packs so their hands are free. The GoLite Chrome Dome was quite popular thanks to providing sun protection as well as protection from rain. If you use an umbrella, make sure it is sufficiently durable for the trail. Some of the best are made euroSchirm which is marketed under the brands such as Birdiepal and Swing Trek LiteFlex. I found the Montbell Trekking Umbrella has a good balance between small/light and adaquate canopy size.
Rain Shell Materials
There is a wide variety of materials used in rain shells. In a perfect world there would be materials which would prevent rain from entering but let you vent perspiration. This is the dream offered by waterproof / breathable (WP/B) materials. Alas, WP/B materials don’t live up to their hype. Even the very best WP/B materials (eVENT, Gore Shakedry) can be overwhelmed by aerobic activities. Many WP/B will be overwhelmed if you do much more than stand around. This is why many WP/B jackets have side or pit-zips which enable the wearer to vent heat and internal moisture when activity levels will overwhelm the materials ability to move the moisture.
Waterproof breathable jackets are breathable only so long as their DWR continues to function. Basic use will degrade the DWR over time. Rough conditions such as bushwacking can significantly speed up this process. This is why you rarely see WP/B being used by people who work in very harsh conditions like the Alaskan, Australian outback, fishing trawlers, etc. You will typically find them using very durable non breathable waterproof materials, or they use something that keeps warm and mostly dry such as the modern military layering system using EPIC fabrics.
Common materials used in shells today ordered roughly by their breathability.
- Softshells: See my soft-shell post for more information about this approach. The use of soft shells was initially prompted by experienced climbers in the UK when facing cold, wet conditions while engaging in heavy work. Paramo is well known in the UK for providing good rain protection in very cold conditions. These sorts of shells only make sense if you are wearing them continuously. If they are something you will be putting on only if it starts to rain, then you should go with a traditional rain shell which will be lighter weight and more waterproof.
- Gore Shakedry such as used in the ArcTeryx Norvan SL. The first rain shell I have found that is almost as breathable as an unlined windshell. Unfortunately the material is not very durable, so it’s not recommended for backpacking, climbing, going off trail, etc. I have used it on shorter on-trail trips. The Norvan SL has a design flaw which results in leakage through the zipper, but it’s still pretty amazing, though pricy shell.
- Polartec NeoShell: Polartec claim’s it’s around twice a breathable as eVENT. I have no experience with it. The people I know who have used it say when it’s dry outside it works well, but in a rain rainstorm it becomes much less breathable and wets out quickly. I would recommend skipping this material.
- Zpacks Vertice is reported by some to be the more breathable of any material currently on the market. By the numbers it sound better than Gore Shakesdry, but in practice I found my Norvan SL more comfortable. In fact, I think eVENT DVL subjectively seemed equal.
- eVENT: used to be my favorite WP/B material, especially eVENT DVL. I used a Westcomb Focus LT Jacket for several years. I found that eVENT to be more comfortable than Gore-Tex PacLite, Propore, or any other PU shell I tried, but it wasn’t the miracle I had hoped. In particular, I found that when engaged in heavy work, I still need pit zips (which it doesn’t have) to avoid internal condensation. That said, I found that when my activity level dropped that the moisture was able to dissipate. I found I was equally comfortable in a jacket made from eVENT DVL without pit zips as I was wearing a jacket made from Montbell BreezeTec with pitzips open. The pricy Hyper Mountain Gear The Shell combines eVENT with a non-woven shell which should be less prone to wetting out in extended rain and be reasonably durable even though it’s extremely light weight. Don’t know how The Shell’s breathability compares to eVENT DVL which I found superior to classic three layer eVENT materials.
- Columbia Outdry Extreme is reported to have breathability almost as good as eVENT but due to the membrane of the outside, be immune to wet out which makes it better than the typical eVENT bonded to nylon shell for multi-day back country adventures in constant rain. So far I have limited experience with Outdry Extreme and can’t confirm this.
- Microporous polypropylene WPB nonwoven fabric (Propore): Strickly speaking Propore is a specific formulation… but I going to use it as a generic term in this paragraph to save space. Propore is the cheapest water proof breathable material available today. In it’s lightest form it is also very breathable and doesn’t wet out. I have been more comfortable wearing a light Propore jacket in warm weather than a 40 denier eVENT shell and have experience wet clothing dry while being worn under a Propore Jacket. The first rain suit I discovered using the material was the Rain Shield O2 (which I believe uses the lightest weight Propore manufactured). You can get a complete Dri Ducks Ultralite (jacket and pants, 11oz) for less than $20! There are also the slightly heavier, more durable, more expensive Frogg Toggs. The down sides of Propore garments? First, the fabric is very flimsy. They are not appropriate for abrasive conditions: climbing and off-trail travel through shrub country is right out, though they have been fine cross country in relatively open conditions. Some people wear wind shells over their Propore rain gear to protect against rips. My Rainshield O2 jacket has several locations it had worn through after a just a few weeks of continuous use. With the aid of duct tape patches I was able to keep the garment alive for a couple years. The first place I have had the fabric wear out is around the wrists. Another issue with Propore rain gear is that the cut tends to be awful: the DriDucks tend to be huge, with the Rainshield O2 cut too tight with uncomfortable seams.
- Air Permeable PU: Some versions of Toray’s Entrant, Pertex Shield, and related materials like Montbell BreezeTec has some air permeability and are able to directly vent water vapor rather that requiring the vapor to condense and then be transported out. While not as breathable as eVENT, these materials are noticeably better than the traditional PU garments. Not only are they more breathable, but they tend to feel less clammy if you happen to have the material directly against your skin. Reports about the MemBrain Strata claim breathability similar to Montbell’s BreezeTech while being lighter and more durable, but I haven’t seen detail analysis which bears this claim out.
- Gore-Tex Pro/PacLite/Standard: For the last twenty years, Gore-Tex Waterproof/Breathable (WPB) rain gear has been successfully marketed as the gold standard for outdoor activities in the USA. In theory Gore-Tex keeps the rain off you, but “breaths” so your perspiration escapes. Alas, if you are engaged in aerobic actives, you will find that Gore-Tex does not breath enough and you will likely get soaked in sweat. Gore Pro is the most durable version of Gore-Tex and surprisingly more breathable than PacLite. On the other hand PacLite is often bonded to lighter materials, so it can seem to be more breathable and PacLites seem to buffer moisture well, so if you engage in brief aerobic activities, you are likely not to notice you have briefly overwhelmed PacLite’s ability to move moisture. I can’t imagine purchasing a Gore-Tex Classic jacket these days since there are a number of PU based jackets which are as breathable and less expensive.
- PU Coated Jackets: Most WP/B jackets that aren’t branded as GoreTex or eVENT are PU. The biggest issue with PU jackets is that water vapor has to condense before being transported across the material. This limits the speed the moisture can be move, makes the jacket feel a bit clammy, and when facing severe cold the water can end up such inside as frost because it freezes more quickly than it can be transported. Marmot PreClip which historically has been one of the better values when you factor price (<$100), design (includes features such as as pit zips and a good hood), quality (like fully taped seams), and reasonably light weight (~12 oz). The downside of the less expensive Marmot jackets is that the DWR is so/so… after a number of hours in hard rain they tend to wet out. Most PU coated jackets are not as breathable as Gore-Tex and can be easily overwhelmed by aerobic actives.
- Non-Breathable Waterproof Jackets: I suppose these are cheap, durable, can be very light. I would never use a non breathable jacket, but some people do. If you are engaged in aerobic activities while wearing a non breathable jacket, whatever is under the jacket will get soaked in sweat. Many options which are fairly cheap.
More Info / Details
The Rain Jacket Guide at backpackers.com is a good overview of rain gear. Allan’s Best Durable Light Weight Rain Jackets is a nice summary of a number of high quality, light weight jackets currently on the market.
Roger Caffin from down under has written a nice but now somewhat dated Rainwear FAQ. There is a nice article by Richard Nisley called A New Paradigm for Understanding WPB Fabrics with a corresponding thread which discussed the article. Patagonia wrote a nice article entitled What is Percent of Naked? which describes a way to characterize shells which captures both wind permeability and water vapor transmission. A study found that air permeability was a better predictor of comfort than vapor transmission rates. Andrew Skurka wrote an article Breathability: It’s Mechanism and Limitations.
Some material which is dated but still interesting includes articles from BPL about Waterproof Breathable Fabric Technologies , ORWM 2011 new WPB fabric technologies, and High Exertion Moisture Accumulation. I found the Breathability Graphs and Temperature Dependent Water Vapor Diffusion from the Soldier Systems Center to be interesting.
The cheapest rain gear for short periods of rain are those cheap ($1) and light weight (2 ounces) plastic emergency ponchos or a plastic garbage bag with a hole cut in the bottom. You can also find more durable ponchos made from thin PVC for around $3 (weights around 8oz) at hardware or outdoor stores. The cheapest water proof breathable option I know of are Dri Ducks which are less $20 for jacket and pants.