Waterproof ratings explained, and why most brands do not publish one

What the number actually measures

The test is more literal than people expect. A square tube is placed on the fabric and filled with water, and the height of water the fabric holds before droplets appear on the other side is the rating in millimeters. A 10,000mm fabric held back a ten-meter column. That is it.

It is a useful comparative figure and a poor absolute promise, for three reasons. A garment leaks at its seams and zips long before its fabric fails. The finish on the outside that stops the face fabric soaking up water is a separate system that wears off. And you are not standing under a ten-meter column of water; you are kneeling in wet snow, which applies pressure in a completely different way.

What rating you actually need

The single biggest variable is not the mountain but the snow. Cold snow is dry and brushes off; a spring afternoon at low altitude is effectively rain, and rain is what finds the limits of a cheap garment. If your family skis in January in Colorado, a modest rating is genuinely fine. If you ski in March in the Northeast, buy the higher number.

The second number, and why it matters as much

Ratings are frequently published as a pair, such as 10,000mm / 10,000g. The second figure is breathability: grams of water vapor that pass through a square meter of fabric in twenty-four hours. Higher means more sweat escapes.

This matters more than beginners expect, because most of the time a skier feels wet, they are wet from the inside. A jacket with a high waterproof number and low breathability keeps snow out and traps sweat, which is exactly as cold as being rained on. The activity level decides how much you need: a beginner spending the day on green runs sweats less than someone hiking a ridge, so a moderate figure is fine.

Seams are where garments actually leak

Every stitch is a hole. Waterproof garments address this with tape bonded over the seams on the inside, and there are three levels of it:

• Fully taped or fully sealed. Every seam. What a genuine all-weather garment publishes.
• Critically taped or critically sealed. The shoulders, hood and seat, where water sits, but not every seam. Very common on mid-priced outerwear, and honest when it is published as such.
• Untaped. Water gets in at the stitching. Acceptable in cold dry snow, not acceptable in spring.

This is scored directly in our rankings, and it is one of the axes where the cheaper picks on this site score honestly rather than well: our jacket roundup shows which of them publish sealed seams and which publish critical taping only. The working is printed under each pick.

The finish that fails first

Underneath the ratings is a durable water repellent finish on the outer face of the fabric. It is what makes water bead up and roll off. It is not the waterproof layer, it wears off with use and dirt, and it is the thing that fails long before any membrane does.

When a jacket “stops being waterproof” after two seasons, this is almost always what has happened. The fix is a wash and some warmth, not a new jacket, and it works. The washing page has the process step by step and it is the highest-value gear-care job in this whole category.

When a maker publishes nothing at all

Here is the awkward truth about this specification, and it is why this page exists rather than a chart of brands. Several of the largest outerwear brands publish no millimeter rating whatsoever for their consumer ski jackets. They name their own proprietary waterproof-breathable technology and leave the number off.

Across the outerwear on this site, only two products publish a number: one jacket publishes 10,000mm and one pair of pants publishes 3,000mm. Everything else publishes a technology name, and in several cases a seam construction, and no rating. We record that as “not published” rather than guessing, which means those products score nothing on that input instead of being handed a number we invented.

What to do about it as a buyer:

• Do not read absence as failure. A large brand’s proprietary laminate is usually a genuine waterproof-breathable membrane; it is simply not published as a figure.
• Look at what they do publish instead. Seam construction and the named technology are both real information.
• Weigh the published number when it exists. A brand that publishes 10,000mm has made a specific claim you can hold it to. That is worth something on its own.
• Check the return policy. Genuinely the most practical advice on this page for a garment with no published figures.

Coating against laminate, briefly

Two constructions produce these numbers. A polyurethane coating is sprayed or rolled onto the inside of the face fabric: cheaper, and more sensitive to heat and harsh detergent. A laminate bonds a separate membrane to the fabric: more durable, more breathable, more expensive. Most budget family outerwear is coated and most premium outerwear is laminated, and for five days a year on cold snow a coated garment is genuinely fine as long as you wash it gently.

Pants have a different requirement from jackets

Pants sit in the snow. Every fall, every chairlift, every ten minutes helping a child with a boot buckle. The seat and the knees take far more sustained water contact than any part of a jacket, and pressure from sitting drives water through fabric that would shrug it off standing up.

So if you are dividing a budget, put the higher rating on the pants rather than the jacket. This is genuinely counterintuitive and it is the single most useful thing on this page. Our pants roundup covers what each pair publishes, and the shell against insulated question is the other axis of the same decision.