Although all of the rainwear discussed in this article is "waterproof-breathable," there are definite limits to their breathability. Here are a few rainwear facts to keep in mind:
- While many WP/B garments will be comfortable at lower activity levels and cool/overcast/breezy conditions, all of them will be a sauna inside if you wear them while hiking uphill carrying a pack in warmer temperatures.
- PTFE laminates (like eVENT and Gore-Tex) breathe better than most other technologies, which means garments have a wider comfort range before they get steamy inside.
- Ventilation is more important than fabric breathability. Opening pit zips, core vents, and a full front zipper make a huge difference in maintaining comfort.
- Carrying a backpack interferes with fabric breathability and garment ventilation a lot.
- We perspire a lot more from our torso area than from our legs. Therefore, we can be comfortable with less breathable (and cheaper) rain pants.
- PTFE laminates (Gore-Tex and eVENT) require maintenance (cleaning and restoration of the surface DWR) to keep them waterproof.
- When only showers are expected, a highly water-resistant windshirt is much more breathable than any WP/B rainwear that has a membrane.
The bottom line is that "highly breathable" rainwear is not a silver bullet. Any highly breathable jacket with minimal ventilation options will easily be overwhelmed by perspiration at higher exertion levels. Ventilation is critical to making a jacket comfortable, especially when hiking uphill carrying a backpack. Carrying a backpack on top of a rain jacket interferes with breathability and ventilation because it covers your backside, the hipbelt seals the bottom, and the sternum strap reduces the effectiveness of opening the front zipper (I usually don't use the sternum strap when I'm wearing a rain jacket so I can get more ventilation when I need it). The situation is exacerbated by the fact that rainwear manufacturers rely on fabric breathability too much and remove ventilation options like pit zips and core vents to save weight and money. Ideally, what we really need is rainwear made of highly breathable fabric, plus several effective ventilation options that work with a backpack, with minimal weight.
- Some Realities
- Polyurethane Laminates
- Rainwear Comparison
- New Rainwear Technologies
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