When shopping for snow gear, you’ll often see numbers like “10K/10K” or “20K/15K” on jackets and pants. But what do they actually mean? This guide breaks down waterproof ratings and breathability so you can choose the right outerwear for your next snow adventure.
What Is Waterproofing?
Waterproof ratings are measured in millimetres (mm) and indicate how much water a fabric can withstand before it leaks. The higher the number, the more waterproof the garment.
| Rating | Conditions Best Suited For |
|---|---|
| 5,000mm | Light rain or dry snow |
| 10,000mm | Moderate rain and snow |
| 15,000–20,000mm | Heavy rain, wet snow, blizzards |
Pro tip: Look for fully taped seams and DWR (Durable Water Repellent) coatings for added protection.
What Is Breathability?
Breathability is measured in grams (g) and refers to how much moisture (sweat) can escape from the inside of your jacket. A higher number means better ventilation and comfort.
| Rating | Activity Level |
|---|---|
| 5,000g | Low activity (e.g. casual skiing) |
| 10,000g | Moderate activity (e.g. all-mountain) |
| 15,000g+ | High-output activity (e.g. touring, backcountry) |
Fabric Technology: More Than Just Gore-Tex®
While Gore-Tex® is the most well-known waterproof membrane, many brands offer their own high-performance alternatives. These membranes work by blocking water droplets from entering while allowing sweat vapour to escape—keeping you dry inside and out.
What to Choose?
- Beginners or resort riders: 10K/10K is usually enough.
- Backcountry or wet-weather riders: Aim for 15K–20K waterproofing and breathability.
- Spring skiing or high-output riding: Prioritise breathability with venting options.
