How Waterproof & Breathability Ratings Work
When you are shopping for ski or snowboard outerwear, numbers like 10K/10K, 20K/20K, or 30K can look more complicated than they really are.
This guide breaks down what those ratings actually mean, how much waterproofing and breathability you need, and what else to look for when comparing jackets and pants.
Contents
What Do Waterproof & Breathability Ratings Mean?
Most ski and snowboard jackets list two performance numbers. You might see something like 10K/10K, 15K/10K, or 20K/20K.
The first number usually refers to waterproofing. The second refers to breathability.
Higher numbers usually mean better performance, but there is one important catch: testing methods are not perfectly standardized between brands. Use the numbers as a useful comparison tool, not as the only thing that determines whether a jacket is good.
A quick comparison of 10K/10K and 20K/20K waterproof and breathability ratings for ski and snowboard outerwear.
How Waterproof Ratings Work
Waterproof ratings are normally measured in millimeters. The basic laboratory test measures how tall a column of water can sit on top of the fabric before water starts pushing through it.
So if a fabric is rated at 20,000 mm, it can theoretically resist a much taller column of water than a fabric rated at 5,000 mm.
Waterproof ratings are measured by how much water pressure a fabric can withstand before moisture passes through it. A higher millimeter rating generally means greater waterproof protection.
Waterproof Rating Chart
| Waterproof Rating | General Protection | Typical Conditions |
|---|---|---|
| 0–5K | Minimal to light water resistance | Dry snow, very light precipitation, fair weather |
| 6K–10K | Basic waterproof protection | Light rain, average snow, typical resort use |
| 11K–15K | Good all-around waterproofing | Moderate storms, regular snow days, longer days outside |
| 16K–20K | High waterproof protection | Wet snow, storm days, wetter mountain climates |
| 20K+ | Very high waterproof protection | Heavy precipitation, wet snow, high exposure and pressure |
Ski Pro recommends at least 5K for ski and snowboard outerwear, but for most riders shopping today we would look at 10K as a much more useful starting point. A 10K jacket gives you enough protection for normal resort riding without jumping immediately into high-end technical outerwear.
How Breathability Ratings Work
Keeping water out is only half the job. Your jacket also has to deal with moisture coming from you.
Skiing and snowboarding generate heat and sweat. If that moisture cannot escape, you can end up wet from the inside even though your jacket never leaked.
Breathability is commonly rated in grams per square meter over 24 hours. A 20K breathability rating generally means more water vapor can escape through the fabric than with a 10K fabric.
5K–8K Breathability
Usually enough for casual, lift-served riding where you are not working up a huge amount of heat.
10K–15K Breathability
A better choice for more active riders, hiking for terrain, and people who tend to run warm.
20K+ Breathability
Best suited to high-output activities like touring, splitboarding, and long days where moisture management really matters.
Breathability testing varies considerably between companies and laboratories, so comparing the exact numbers between unrelated fabric technologies is not always apples to apples. They are still useful for understanding the general performance level of a garment.
Add moisture vapor / breathability graphic here
How Much Waterproofing & Breathability Do You Need?
The answer really depends on where you ride, how hard you ride, and what kind of weather you are willing to ski or snowboard in.
| Rider Type | Good Starting Point | Why |
|---|---|---|
| Occasional Resort Rider | 10K / 10K | Good all-around protection for normal resort conditions |
| Frequent Resort Rider | 15K / 15K | More protection for full days and changing weather |
| Wet Climate / Storm Rider | 20K / 20K+ | Better for wet snow, long storms and repeated exposure |
| Touring / High-Output Rider | 20K+ Breathability | Better moisture management when climbing or hiking |
On the other hand, if you spend every storm day outside, ride in wet climates, wear a backpack, or hike for terrain, stepping up in waterproofing and breathability makes a lot more sense. Backpack straps, sitting on wet chairlifts, falling in snow, and wind all add pressure that can expose weaker waterproof fabrics.
What Is DWR?
DWR stands for Durable Water Repellent. It is the treatment on the outside face fabric that makes water bead up and roll off instead of immediately soaking into the material.
DWR is not the waterproof membrane itself. Think of it as the outerwear's first line of defense.
Dirt, body oils, chairlift wear, backpack straps, and normal use can eventually reduce DWR performance. When that happens, the face fabric can start looking soaked even though the waterproof membrane underneath may still be doing its job.
Why Seam Taping Matters
A jacket can use great waterproof fabric and still leak if water gets through the stitching.
Every sewn seam creates tiny needle holes. Seam tape covers those holes from the inside so water cannot work its way through them.
Fully Taped Seams
Every seam is sealed. This gives you the highest level of weather protection and is what we would look for in serious storm outerwear.
Critically Taped Seams
Only the areas most exposed to weather are taped, such as the shoulders, neck, and upper body. This can still work well for casual resort riding.
Seam construction is one reason you should not judge outerwear on the waterproof number alone. :contentReference[oaicite:5]{index=5}
2L vs 2.5L vs 3L Outerwear
You will also see jackets and pants labeled 2L, 2.5L, or 3L. That refers to how the waterproof membrane, face fabric, and inner protection are put together.
2-Layer
The outer face fabric and waterproof membrane are bonded together, while a separate liner sits inside. This is common in resort jackets and insulated outerwear.
2.5-Layer
Uses the face fabric and membrane with a lightweight printed or textured inner protective layer. It is often used in lightweight rainwear.
3-Layer
Face fabric, membrane, and inner backer are all bonded together. This usually creates a lighter, lower-bulk technical shell that is popular for serious skiing, snowboarding, and touring.
Ski Pro notes that 2L and 3L membrane constructions are common choices for durable snow outerwear, while 2.5L designs tend to show up more often in ultralight rain garments.
What About GORE-TEX?
GORE-TEX is a specific family of waterproof and breathable membrane technologies from W. L. Gore. It is not a generic term for every waterproof jacket.
GORE-TEX membranes are laminated to outer fabrics and designed to block liquid water while allowing water vapor to move out. Different GORE-TEX constructions are built for different combinations of durability, weather protection, breathability, and weight.
GORE-TEX is a proven option, but it is not the only good waterproof technology. Many outerwear companies now use their own membranes and fabric systems that can also offer excellent performance.
The Bottom Line
Waterproof and breathability ratings are useful because they give you a quick way to compare technical outerwear, but they are not the whole story.
For most resort skiers and snowboarders, 10K/10K is a solid place to start. Move toward 15K or 20K if you ride frequently, spend full storm days outside, or deal with wetter snow. If you tour, hike, splitboard, or work hard enough to sweat regularly, breathability becomes just as important as waterproofing.
Then look at the rest of the jacket or pant: seam sealing, vents, DWR, construction, fit, and overall build quality. That is what turns a good fabric into good outerwear.
Need Help Choosing Ski or Snowboard Outerwear?
You do not necessarily need the biggest waterproof number you can find. You need outerwear that matches where you ride, how often you ride, and the conditions you actually go out in.
Shop ski and snowboard clothing at Ski Pro or stop into one of our stores and let our crew help you compare jackets, pants, bibs, and technical shells.
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