What does a waterproof rating mean on a jacket?

A waterproof rating indicates how much water pressure a fabric can withstand before it starts to leak, measured in millimetres (mm) using the hydrostatic head test. The higher the number, the more waterproof the jacket is considered to be.

What is considered a good waterproof rating for outdoor jackets?

A waterproof rating of around 10,000mm is suitable for many everyday outdoor activities, including walking, hiking and resort skiing. Choose 15,000–20,000mm or more for heavy rain, wet snow and prolonged exposure.

How is breathability measured in waterproof clothing?

Breathability is measured by the Moisture Vapour Transmission Rate (MVTR), which shows how much water vapour can pass through a square metre of fabric in 24 hours, usually expressed in g/m²/24h. Higher numbers indicate better breathability.

Can a jacket be both waterproof and breathable?

Yes. Modern waterproof jackets use membranes and coatings that are designed to prevent liquid water from entering while allowing some water vapour to escape.

What is the difference between waterproof, water-resistant, and water-repellent jackets?

Waterproof jackets prevent all water penetration, water-resistant jackets can handle light rain but not prolonged exposure, and water-repellent jackets have a surface treatment that causes water to bead and roll off but may not withstand heavy rain.

Why do I feel wet inside a waterproof jacket?

Moisture inside a jacket may come from sweat and condensation rather than rain entering from outside. This can happen when the jacket’s breathability is too low for your activity, when you wear non-breathable layers underneath or when the conditions are warm and humid.

How do I know if my jacket is truly waterproof?

Check for a hydrostatic head rating of at least 1,500mm (the minimum for “waterproof” by British standards), fully taped seams, and a reputable membrane such as GORE-TEX or similar.

What should I look for in a waterproof jacket?

Look for a suitable waterproof and breathability rating, fully taped seams, a well-fitting hood, adjustable cuffs and a reliable zip. The construction and intended use of the jacket are just as important as the headline rating.

What is the best waterproof jacket for hiking, skiing, or mountaineering?

For hiking, a jacket with at least 10,000mm waterproof rating and good breathability is recommended. For skiing or mountaineering, look for 15,000–20,000mm or higher, with equally high breathability ratings.

How long do waterproof jackets stay waterproof?

Waterproof performance can reduce over time because of dirt, abrasion, washing and general wear. Cleaning the jacket correctly and renewing its DWR (Durable Water Repellent) treatment can help maintain performance, but a damaged or deteriorated membrane may eventually need replacing.

Waterproof Rating and Breathability Explained

Choosing outdoor clothing can be difficult when product descriptions are full of technical terms. Waterproof ratings, hydrostatic head, breathability and MVTR all describe how a garment performs in wet weather, but what do these terms actually mean?

This guide explains what waterproof ratings mean, how they are measured, what the numbers mean in real-world conditions, how waterproof, water-resistant and water-repellent clothing differ, how breathability is measured, and how to choose the right waterproof jacket for hiking, skiing and other outdoor activities.

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What is a Waterproof Rating?

A waterproof rating shows how much water pressure a fabric can withstand before water starts to pass through it. The rating is measured in millimetres (mm) and is also known as the fabric’s hydrostatic head.

For example, a jacket with a 10,000mm waterproof rating has fabric that can withstand the pressure created by a 10-metre column of water before it begins to leak.

A higher number generally means greater resistance to water pressure. However, the rating only describes the fabric or membrane under laboratory conditions. The jacket’s seams, zips, hood, cuffs and overall construction also affect how well it performs in rain and snow.

A high-rated fabric may still let water in if:

The seams are not fully taped.
The outer fabric has become worn or damaged.
The zip is not water-resistant.
The waterproof membrane has deteriorated.
The garment has not been cleaned or maintained correctly.

How Are Waterproof Ratings Measured?

Waterproof ratings are measured using a laboratory test called the hydrostatic head test.

During the test:

A section of fabric is placed beneath a tube of water.
The water level is gradually raised.
Increasing water height creates greater pressure on the fabric.
The test records the point at which water begins to pass through.
This measurement becomes the fabric’s waterproof rating in millimetres.

If water penetrates the fabric when the water column reaches 15,000mm, the material receives a 15,000mm waterproof rating.

The test provides a useful way to compare fabrics, but it cannot reproduce every condition a garment may experience outdoors. Pressure from backpack straps, kneeling in wet snow, abrasion and prolonged rainfall can all affect performance.

Waterproof Ratings Explained: What Do the Numbers Mean?

The right waterproof rating depends on the weather, activity and amount of pressure placed on the garment. A jacket for occasional city use does not need the same level of protection as one designed for ski touring or mountaineering.

Waterproof Rating	Level of Protection	Suitable Conditions
Up to 5,000mm	Basic protection	Light showers, dry snow and short periods outdoors
6,000-10,000mm	Moderate protection	Light to average rain, snow and everyday outdoor use
11,000-15,000mm	Good protection	Moderate rain, wet snow and longer outdoor activities
16,000-20,000mm	High protection	Heavy rain, wet snow and more demanding conditions
20,000mm+	Very high protection	Prolonged exposure, heavy rain, wet snow and high pressure conditions

Is a higher waterproof rating always better?

Not necessarily. A higher rating can provide greater protection, but it may also increase the garment’s price, weight or stiffness. The most suitable rating is the one that matches your activity and the weather you expect to encounter.

For example:

A 5,000mm jacket may be suitable for short walks and light showers.
A 10,000mm jacket is a practical choice for commuting, hiking and resort skiing.
A 15,000mm jacket offers more protection for wet conditions and longer days outdoors.
A 20,000mm or higher jacket is suited to severe weather, mountaineering and backcountry skiing.

Waterproof, Water-Resistant and Water-Repellent

The terms waterproof, water-resistant and water-repellent have different meanings. Understanding the difference can help you choose the right outdoor clothing.

Waterproof clothing is designed to prevent water from passing through the fabric when used in wet conditions. It usually combines a waterproof membrane or coating with features such as taped seams, an adjustable hood and water-resistant zips.

Waterproof garments are the best choice for:

Heavy rain.
Wet snow.
Long hikes.
Skiing and snowboarding.
Mountaineering.
Prolonged exposure to poor weather.

No garment remains completely waterproof in every situation. Damage, wear, poor maintenance and water entering through openings can all reduce protection.

Water-resistant clothing can withstand a limited amount of rain or moisture. It may be suitable for light showers, short journeys and dry conditions, but water can eventually pass through during prolonged or heavy rain.

Water-resistant jackets are often lighter and more flexible than fully waterproof jackets. They can be useful for everyday wear, travel and low-intensity activities.

Water-repellent fabric causes water droplets to bead and roll off the surface. This is usually achieved with a Durable Water Repellent (DWR) treatment.

A water-repellent finish can help prevent the outer fabric from becoming saturated, but it does not make a jacket fully waterproof. It is most suitable for light rain, splashes and short periods outside.

What Is Breathability?

Breathability describes how easily moisture vapour can escape from inside a garment.

When you walk, run, hike or ski, your body produces heat and sweat. If that moisture cannot escape, it can build up inside your clothing and leave you feeling damp, clammy or overheated.

A breathable jacket allows water vapour from sweat to move through the fabric while helping to prevent rain and snow from entering from the outside.

Breathability is particularly important for high-energy activities such as:

Running.
Hiking uphill.
Climbing.
Ski touring.
Snowboarding.
Fast-paced walking.
Mountaineering.

Waterproof and breathable fabrics commonly use a membrane or coating with a structure that allows water vapour to pass through while blocking liquid water.

What does MVTR mean?

Breathability is often measured using Moisture Vapour Transmission Rate, or MVTR.

MVTR shows how much water vapour can pass through one square metre of fabric in 24 hours. It is usually written as:

g/m²/24h

A jacket rated at 20,000g/m²/24h is designed to allow more moisture vapour to escape than one rated at 5,000g/m²/24h.

Breathability Rating	Breathability Level	Suitable Use
Up to 5,000g/m²/24h	Basic	Low-intensity activities and casual use
5,000–10,000g/m²/24h	Moderate	Everyday wear, walking and resort skiing
10,000–15,000g/m²/24h	Good	Hiking, active skiing and changeable conditions
15,000–20,000g/m²/24h	Very good	High-output activities and active outdoor use
20,000g/m²/24h+	Excellent	Ski touring, mountaineering and intense activity

MVTR ratings are useful for comparing products, but they do not tell the whole story. Temperature, humidity, wind, base layers, activity level and the fit of the garment can all affect how breathable a jacket feels.

Waterproofing and Breathability: Finding the Balance

Waterproofing and breathability perform different jobs:

Waterproofing helps stop rain and snow entering.
Breathability helps sweat and moisture vapour escape.

A jacket with strong waterproof protection but low breathability may keep rain out while trapping sweat inside. A highly breathable jacket with limited waterproofing may feel comfortable during activity but provide inadequate protection in heavy rain.

The best balance depends on how and where you plan to use the jacket.

For example, someone skiing slowly on groomed runs may prioritise insulation, waterproofing and comfort. Someone ski touring uphill or hiking in warm weather may need a higher breathability rating to manage sweat and heat.

What are 2-layer, 2.5-layer and 3-layer Fabrics?

Waterproof and breathable garments are made using different fabric constructions. The main types are 2-layer, 2.5-layer and 3-layer designs.

A 2-layer fabric bonds the outer fabric to a waterproof membrane. A separate lining or mesh is added inside to protect the membrane from body oils and abrasion.

Best for:

Everyday waterproof jackets.
City commuting.
Light hiking.
General outdoor use.

Two-layer jackets are often comfortable and affordable, although they can be heavier and less packable than other constructions.

A 2.5-layer fabric uses a lightweight protective print or coating on the inside of the waterproof membrane instead of a separate lining.

Advantages include:

Low weight.
Easy packability.
Efficient use of space.
Suitability for travel and backpacking.

Two-and-a-half-layer jackets may feel less comfortable against bare skin and may not be as durable as 3-layer garments.

A 3-layer fabric bonds the outer material, waterproof membrane and inner protective layer together. This creates a durable and high-performance construction.

Best for:

Mountaineering.
Ski touring.
Backcountry skiing.
Technical hiking.
Expeditions.
Severe weather.

Three-layer jackets are often more expensive, but they provide a strong combination of durability, waterproofing and breathability.

Choosing a Waterproof Jacket

When choosing a waterproof jacket, consider the following:

The weather conditions you expect.
How active you will be.
How long you will wear the jacket.
Whether you need a lightweight or packable design.
The jacket’s seam and zip construction.
The number and type of fabric layers.

How much room you need for insulating layers.

For commuting, travel and short walks, a jacket rated around 5,000–10,000mm may provide enough protection for light to moderate rain.

Look for practical features such as:

An adjustable hood.
Secure pockets.
Comfortable cuffs.
A two-way or water-resistant zip.

Space for a light midlayer.

For hiking and longer days outdoors, consider a jacket with at least a 10,000mm waterproof rating and a breathability rating of around 10,000g/m²/24h or higher.

If you regularly hike in exposed or wet conditions, a rating of 15,000mm or more may offer better protection.

Features such as pit zips, a helmet-compatible hood, adjustable cuffs and a longer back panel can also improve comfort and weather protection.

Ski and snowboard jackets need to cope with snow, chairlift seats, falls and prolonged exposure to cold weather. A waterproof rating of 10,000–20,000mm is suitable for many resort conditions.

Choose a higher rating if you:

Ski or snowboard in wet climates.
Spend long days on the mountain.
Frequently sit or kneel in wet snow.
Take part in backcountry or off-piste activities.
Generate a lot of heat while skiing.

A breathability rating of 10,000–20,000g/m²/24h is a useful guide for active winter sports. Higher breathability is especially valuable for ski touring and other high-output activities.

Mountaineering and expedition jackets need high levels of protection, durability and breathability. A rating of 20,000mm or higher, combined with a high breathability rating, is suitable for demanding conditions.

Look for:

A durable 3-layer construction.
Fully taped seams.
A helmet-compatible hood.
Water-resistant zips.
Adjustable cuffs and hem.
Reinforced areas.
Space for multiple layers.
Reliable storm protection.

How to Maintain a Waterproof Jacket

A waterproof jacket can lose performance if it becomes dirty, damaged or saturated with water. Follow the care instructions supplied by the manufacturer.

General maintenance tips include:

Wash the jacket using the recommended cleaning product.
Avoid standard fabric softener unless the manufacturer allows it.
Check the seams, cuffs and zips for signs of damage.
Reapply a DWR treatment when water stops beading on the outer fabric.
Dry and store the jacket according to the care instructions.
Repair small tears before they become larger.
Do not use excessive heat unless the manufacturer recommends it.

A worn DWR finish does not always mean the waterproof membrane has failed. It may simply mean the outer fabric needs cleaning or reproofing.

All You Need To Keep Dry + Cool On The Slopes

Understanding waterproof ratings and breathability is essential for selecting the right outdoor clothing, ensuring you stay dry, comfortable, and safe in any weather. By learning how these properties are measured and what the numbers mean, you can make informed decisions about your gear and enjoy your adventures with confidence. Whether you are braving a downpour in the city or tackling a snowy mountain trail, the right jacket will keep you protected and ready for whatever nature has in store. Explore the expert range of waterproof and breathable jackets at Snow+Rock to find the perfect gear for your next adventure12.