Waterproof Basics : Rain Jackets

Rain gear is an investment, plain and simple. What's not so simple? Sifting through brands discerning which fabrics and features will best accommodate your rainy-day lifestyle. If you take time to appreciate the technology involved, however, it’s actually pretty interesting stuff, and the investment seems worthy. Why are quality rain jackets so expensive? Let’s take a look.

First, please remember : No fabric will keep you completely dry. A jacket made of solid rubber might, technically -- but once you start to sweat, the material will suffocate your skin and you’ll panic like Will Ferrell inside a glass case of emotion. So while the rain won’t get you wet, your own perspiration will. That’s why breathability in waterproof or water-resistant fabrics is a major factor in deciding which rain jacket to purchase, based on your level of activity and the climates you’ll encounter along the way.

Thankfully, we have scientists for this kind of thing. Here are three ratings commonly used to measure how effective a fabric is at withstanding moisture, pressure, and breathability.  How do you choose which to pay attention to? Consider these scenarios :

If you’re buying a jacket for leisure hiking or jogging in the rain, the mm/24 rating for moisture is a good one to use, since you’ll only encounter moisture, not necessarily pressure (unless it’s windy). A novice snowboarder might look to the psi rating for pressure, if they predict many forceful contacts with the snow. A backpacker travelling in wet conditions, however, would find both ratings helpful, as their pack creates extra friction along their back and shoulders, the pressure and moisture together making the garment more permeable. But each scenario would benefit from a high breathability rating -- g/m²/24 (the more grams, the better). The only time you’d want less breathability, i.e. fewer grams, is in cold, dry climates, so your body heat will stay inside the jacket and keep you warm.

Rating Systems Explained -- get ready for some science!
mm/24
Moisture :  how many millimeters of water the fabric can withstand in 24 hours

psi
Pressure :  how many pounds per square inch the fabric can withstand when it’s wet

g/m²/24
Breathability :  how many grams of water vapor pass through the fabric in 24 hours

Since manufacturers use their own methods as well as independent labs for testing, truly standardized ratings can be hard for consumers to find. Because of this, it’s more effective to compare within a brand, or within the same group of fabrics, than to compare different brands to each other. However, if you pinpoint a range within each rating that is best suited for your activity and climate (look to brand websites), this will generally be a good predictor for which fabric will produce your desired results.

Adjustable Hood
Boyz n the [Multi-Point Adjustable] Hood

DWR (Durable Water Repellent)
This ubiquitous water repellent treatment allows moisture to bead up and slide down your fabrics, keeping you nice and dry. It’s not waterproof, which does wonders for its breathability. This makes DWR an easy, comfortable solution for getting caught in drizzling rain or snow, and is found on most softshell jackets.

The effectiveness of the manufacturer’s DWR treatment diminishes, however, the more you expose it to inclement weather, dirt, and friction. Not to worry! Consumers can apply their own DWR treatments at home, or even while on the trail. These low-cost solutions are a must for preserving the water-repellency of your gear. Always wash and fully rinse your garments before applying these treatments, so dirt and oils won’t lock in and hinder the effectiveness of the treatment. Check out these DWR sprays and fabric washes that are simple, effective, and super easy to use.

GORE-TEX
This proprietary product from the W.L. Gore Corporation is a top-selling feature for waterproof jackets. It uses a membrane (instead of an outer coating) that is laminated to nylon and polyester face fabrics to create a highly waterproof, somewhat breathable barrier. GORE-TEX utilizes billions of microscopic pores to create different grades of protection, so you can spend money only on the barrier thickness you need.

The thing with GORE-TEX is, it’s waterproof, so you’ll want to be careful how long you keep these garments on. (Especially with footwear, as we’ll discuss in the next installment of this series.) If you plan to wear GORE-TEX garments continuously for days on end, do so only in colder conditions. Wearing GORE-TEX in warmer weather could potentially cause issues with prolonged moisture from body heat.

Taped/Sealed Seams
Needle stitching pokes thousands of tiny holes in your gear, so most outerwear worth their juice has a thin layer of waterproof tape over the top of the stitching to prevent water from trickling in. Without seam sealing, you’ll get wet no matter how waterproof your fabrics are. Some garments utilize seam sealing only in the most critical areas, like the neck, chest, and shoulders, while others boast “fully sealed seams.”

Pit Zips
If you need to sacrifice breathability for a higher moisture or pressure rating (a common forfeiture, for better or worse), make sure your jacket is equipped with zippers under the arms. These allow body heat to escape from critical areas without you having to unzip the main zipper or remove the jacket entirely.

YKK & Waterproof Zippers
Back to that glass case of emotion : faulty zippers give you a general feeling of wanting to give up, on everything. YKK is the most common and reliable zipper system on the market, ensuring a smooth zip every time. Waterproof zippers are something else to consider, but come with mixed reviews. They can be hard to operate, especially larger ones coated with urethane. YKK offers waterproof/water-resistant zipper options that work well, as does Riri, another favored brand. Another option is a storm flap -- if engineered with a no-snag design -- that covers the top of your zipper system with a long strip of waterproof or water-resistant fabric. 

YKK Zipper
YKK, an acronym for the Japanese manufacturer, Yoshida Kogyo Kabushikikaisha

Each of the above features will add cost, so choose wisely. Our upcoming posts in this series will outline water repellency and breathability in footwear as well as sleep systems, so check back often for helpful advice on how best to invest in your rain gear!

Until then, browse our selection of Women's and Men's Rain Jackets with the above knowledge in mind. And remember : the best waterproof-breathable membrane is your very own skin!