The Complete Guide to Outerwear Breathability Ratings

When selecting new outerwear there is an infinite number of colors, styles, and features, but there are really two key technical considerations: the waterproof rating and the breathability rating. Because regardless of what a jacket looks like, if it doesn’t keep you warm and dry then it is not doing its job.

The breathability rating of a piece of outerwear is a quantification of its ability to move moisture away from the body during periods of activity. Coupled with a waterproof rating, these two measurements provide a general estimate of performance that you can use to decide whether a piece of technical outerwear will work for your needs.

But breathability ratings are kind of complicated. What exactly does the rating measure? How is it calculated? So, we sat down and put together this guide to answer some of the most common questions.

What is breathability?

When you're active, your body generates heat. Whether you are playing basketball indoors at room temperature or snowboarding outdoors in sub-zero temperatures, you create moisture vapor when sweat evaporates off of your body.

In the context of technical outerwear, breathability refers to the passage of moisture vapor from your body through the material of the jacket or pants to the outside. This moisture transmission is what keeps you dry. In general, waterproofing and breathability work together to keep you comfortable when snowboarding.

Breathability vs. Wicking

Breathability describes a fabric's ability to allow moisture to escape, based on its construction (weave and pores). Wicking describes a fabric's ability to absorb moisture from the skin and bring it to the surface, based on the fiber itself. It's a distinction worth making for this discussion.

Breathability Ratings Explained

Fabric performance ratings are determined by brands, manufacturers, and independent testing facilities and most top manufacturers (including Burton) have aligned to a standard rating scale that includes two numbers: waterproofing and breathability. But while the scale may have been standardized, the methodologies for determining the actual ratings can vary based on the testing facility and conditions. Because of this, shoppers should consider breathability ratings more as general guidance than concrete recommendations.

Example jacket: 10,000mm/5,000g (often these numbers are abbreviated and displayed as 10k/5k)

Measuring Waterproofing

There are a few approaches for determining waterproof ratings, but most involve placing a 1" x 1" square tube over a swatch of fabric and filling it with water until it begins to seep through the fabric, using the height of the water in the tube (in millimeters) as the waterproofing measurement.

In our example, the jacket has a waterproof rating of 10,000mm.

Measuring Breathability

Measuring breathability is inherently difficult, as factors like temperature, humidity, and atmospheric pressure are most certainly not standardized across manufacturers and testing facilities. With that said, the most common breathability tests involve placing a one square meter swatch of fabric over a container of liquid (typically a simulated sweat solution like calcium chloride), leaving the container in a controlled environment for 24 hours, and then measuring the weight of the container to determine the amount of liquid (in grams) that was able to pass through the fabric. This is known as the Moisture Vapor Transmission Rate, or MVTR.

In our example, the jacket has a breathability rating of 5,000g.

The MVTR Breathability Scale

• 5,000g – 10,000g: Breathability in this range works well for chairlift laps at the resort and moderate outdoor activity that doesn’t involve a high level of exertion.
• 10,000g – 15,000g: This level of breathability will keep you comfortable during more intense aerobic exertion when snowboarding, hiking, or splitboarding.
• +15,000g: Very high breathability ratings are designed for the most strenuous outdoor performance and are engineered to deliver comfort during periods of high exertion.

Alternatively, brands like GORE-TEX® sometimes measure breathability with a system called Resistance to Evaporative Heat Transfer (or RET), with lower being better for more aerobic activities. Note that the RET system is not widely used.

The RET Breathability Scale

• 0 – 4: Very high breathability ratings are designed for the most strenuous outdoor performance and are engineered to deliver comfort during periods of high exertion.
• 4 – 6: This level of breathability will keep you comfortable during more intense aerobic exertion when snowboarding, hiking, or splitboarding.
• +6: Breathability in this range works well for chairlift laps at the resort and moderate outdoor activity that doesn’t involve a high level of exertion.

What level of breathability is best?

While more breathability sounds like it would always be better, the truth of the matter is that the right amount of breathability depends on the situation. If you are snowboarding at the resort and taking laps on the chairlift, you don’t necessarily need very high breathability as you may not be creating too much excess body heat. By contrast, if you are touring in the backcountry and planning for a lot of steep hikes and long traverses, a jacket with a high breathability rating is going to be more comfortable as you exert more energy.

The breathability that you need is all based on the performance necessary for the level of activity you plan to do on a given day. For many riders, having one snowboard jacket for the entire season meets their needs, but for others, having a few different outerwear options for different weather and levels of activity is the way to go. It’s important to note that this decision is largely based on personal preference, so review these breathability ratings again and then go find the perfect outerwear to keep you comfortable all season long.

Pro tip: For climate controlled comfort, check out Burton's Living Lining® jackets, snow pants, and bibs that provide consistent temperature regulation without added bulk.