The Layering System – The Outer-layer

In part one and two of this series we looked at baselayers and mid-layers, and the role they play in keeping you warm and dry. In the final part of this series we complete our journey through the layering system by looking at the outer-layer.

As many will know your outer-layer is commonly some type of waterproof jacket. However, with so many on the market, understanding the role this layer plays will help you make the right choice when kitting up.   


First and foremost your outer-layer provides rain protection. Although some soft-shell style outer-layers and other lightweight jackets are only water resistant (designed for use in marginal conditions) most outer-layers provide 100% waterproofing. For the majority of people the fully waterproof versions offer much better versatility.

As well as waterproofing another important function to help combat the elements is wind-proofing. When you consider a mere 10km/h wind makes 5°C feel more like -2°C you will begin to appreciate its importance. Luckily there are a lot of waterproof jackets in our range that also provide 100% wind-proofing. This greatly reduces the effects of wind-chill and the risk of cooling related issues like hypothermia.

The final benefit a good outer-layer provides is breathability. This is how waterproof fabrics allow perspiration to escape. It is this ability that sets a quality outer-layer apart from a basic waterproof jacket. It’s really quite surprising how wet you can become from perspiration when active in a waterproof jacket. This moisture causes significant discomfort and more seriously rapid cooling.


To really understand the difference between waterproof jackets you need to understand the fabrics they are made from. Most high street jackets use a simple waterproof finish that keeps the rain out (at least to begin with), but get hot and sweaty after a few minutes gentle walking. However, here at Millets our jackets are chosen for their waterproof protection AND comfort, with better levels of breathability and durability so you can stay dry all day.

The most common way to make a fabric waterproof is to apply a good waterproof coating to the fabric. This is a cost-effective way to create a waterproof and breathable jacket suited to everyday use on the hill or around town. Different brands have their own versions of waterproof coatings, and we’ve listed the most popular below so you can keep an eye out for them...


Waterproof Technology

Peter Storm

Storm Shield+



The North Face


Jack Wolfskin




...but hang on a minute, what about Gore-Tex? Gore-Tex fabrics use a special membrane that is bonded to the inside of the outer fabric - it's not just a coating. This gives Gore-Tex two big advantages over traditional waterproof methods; much better breathability and excellent durability.

The Gore-Tex membrane contains millions of tiny micropores which are too small for liquid water to pass through, but are bigger than a water vapour molecule. This allows sweat in the form of vapour to escape from inside the jacket, while still stopping 100% of rain or snow getting in. This is what gives Gore-Tex it's fantastic breathability.

By bonding the membrane to the inside face of the outer fabric, Gore-Tex doesn't wash or rub off over time. This means that with correct washing and drying a Gore-Tex jacket will remain waterproof and breathable for it's entire life. All-in-all Gore-Tex jackets are usually more expensive than coated jackets, but can last a lot longer and give reliable performance throughout the life of the jacket.


The final thing to consider when choosing an outer layer are what key design features you need. This will depend on what you intend to use the jacket for, and will vary depending on the duration, type and intensity of activity you are doing. There is no jacket that will cover ALL eventualities, but with a bit of planning you can get one that covers all the LIKELY uses you will need it for.

The hood of a jacket tells you a lot about its intended use. A thin roll-away hood is good for a short duration but can reduce your visibility and get annoying if you are out all day in the rain. In these cases a hood with a stiffened peak and some adjustment is much more comfortable. For mountain walking, climbing or other high-level use you may also need a wired peak or extra-large hood to fit over a helmet.

The other places to check are around the main zips and the pockets. Storm flaps in front of or behind the main zip will stop water leaking in, or some jackets use a plastic coating on the zip itself to do the same thing. Pocket zips can be protected the same way, and you need to consider what you might keep in your pockets too - if you carry a phone or other water-sensitive device (including maps!) then you definitely need waterproof pockets.

For more active use you need to think about letting excess heat and sweat escape out of the jacket so you stay comfortable and don't overheat. In simple terms this can be done by unzipping the jacket a bit - but that obviously risks letting wind and rain in. Some jackets have extra concealed zips that are better protected from rain. These are usually found on more expensive jackets and located under the armpits.

Finally, if you regularly wear a rucksack then you might want a jacket with chest pockets that are up out of the way of the hip belt, so you can still have easy access to any essentials you need out on teh trail.


Well, that's it! Everything you need to know about the layering system. Got any questions? Don't hesitate to ask in comments below or on Facebook and Twitter.


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