MMO’s Ultimate Winter Layering System

Discover Mountain Mail Order's tried and tested 4-part layering system for cosy winter adventures...

By Tyler Morrissey
CityROCK Johannesburg Shop Manger

The secret to staying toasty on chilly adventures is building a top notch layering system that balances moisture-wicking, wind/rain protection and warmth with breathability and practicality. Sounds a bit complicated… luckily, we’ve done the research and experimentation for you! Read on for Mountain Mail Order‘s tried and trusted four-part layering system that will keep you warm, dry and loving every minute out in Mother Nature…


The base layer is step one – think of it as your second skin. For your base layer we recommend thermals – lightweight, ultra-warm garments designed to wick moisture (i.e. sweat) away from your skin. In hot months, we want our sweat to evaporate and cool us down, but in winter we want to remove moisture from the surface of our skin as quickly as possible to keep the whole system dry and toasty. Moisture-wicking materials use a fancy combination of hydrophobic and hydrophilic fibres to draw moister away from our skin and to the outside of the garment in a thin layer, promoting efficient evaporation.

There are a few options when it comes to base layers – primarily natural fabrics, synthetic fabrics and blends. Synthetic materials are typically lightweight, durable, quick-drying and much cheaper than natural materials. However, natural fabrics like Merino wool (a very popular choice for base layers) are a bit warmer, have built-in odour-resistant properties, excellent moisture-wicking, and can also feel dry for longer in wet conditions – you can read more about the science of synthetics vs natural thermals here. Of course, a happy medium is a synthetic and natural blend, which offers the benefits of natural fabrics with some extra durability and a lower price point.

We recommend going for either pure Merino base layers or a blend of natural and synthetic. Our favourite blended thermals are First Ascent’s Bamboo Baselayers (click here for men’s, here for women’s), which are made from 85% polyester and 15% bamboo fibres for a lightweight, durable and top garment with natural odour-resistance. If you want to go fully natural, we recommend Core Merino and Ice Breaker, along with Nikwax Wool Wash to keep them clean and wicking well.



Fleece is primarily made from polyester and, much like a thermal base layer, is designed to keep you cosy and wick away sweat. This fleece layer thus works with the bae layer to keep you nice and dry. You can opt for a fleece ¼ zip or full zip jacket which makes de-layering a bit more convenient, but zips can create little openings for cold to come through, so you might prefer a fleece pullover.

Fleeces have different weights, measured in grams per square meter (gsm). The three main weights are:

          i.      100 weight = 100gsm (lightweight)
 ii.      200 weight = 200gsm (midweight)
 iii.      300 weight = 300gsm (heavyweight)

The greater the weight, the denser and water the fabric will be. For general around-the-town travel or for some cosiness on a summer night, a 100gsm fleece will do just fine. However, we recommend a 200gsm fleece for winter adventures. A 300gsm fleece is pretty darn bulky and is really only necessary for sub-zero conditions – MMO doesn’t stock 300gsm fleece for this reason, but you can find it in a speciality gear store if you’re planning on heading into the snow.

Our favourite fleeces are the North Face Glacier ¼ Zip Fleece (lightweight) and the First Ascent K2 Powerstretch Jacket ( mid/heavyweight). Both of these use fabrics made by PolarTec created from recycled polyester (yay environment!).


How could we talk about winter adventure gear without mentioning the humble down jacket. Stuffed with either natural down feathers (generally from ducks or geese) or synthetic down, these puffy marshmallows trap warm air and body heat to keep you ultra cosy.

If you’re of the vegetarian or vegan persuasion, you’ll probably want to go for synthetic down – if you want genuine down feathers, make sure to look for the Responsible Down Standard (RDS) logo. Natural down tends to be lighter and warmer than synthetic, but it loses its insulating properties very quickly when wet. Synthetic down is cheaper, vegan-friendly and stands up a bit better to water.

Down jackets have differing fill powers, which refers to how much down it takes to produce the desired insulation effect. Most jackets usually have a fill power of 600 to 800. The higher the fill power, the less down is needed to achieve a specific warmth rating, therefore, the lighter the garment can be. Down is also available in different quality ratings known as the down-to-feather ratio. Most high-end jackets have a ratio of 90% down to 10% feather; the lower the quality, the smaller the percentage of down in the ratio.

We recommend the North Face Thermoball for a synthetic down, and the Ocun Tsunami Down, First Ascent Touch Down and the First Ascent Transit Down for genuine down. The Thermoball and Tsunami also have water-repellant coatings to prevent moisture from seeping through the material and into the feather stuffing.


Now that we’ve got thermals and fleece to keep you warm and dry, and a nice puffy to keep the heat locked in, we need a wind- and/or waterproof shell to keep out the cold air and any rain or snow.

Jackets that are only windproof are generally lighter than rain proof jackets but have lower hydrostatic heads, which is a measure of:

(a) how much water can be poured onto a square metre of fabric without it seeping through (the water column)
(b) how breathable they are (how much air in grams escapes through a square metre of fabric over a 24-hour period)

For your outer shell we recommend something light and durable that can pack up small (for those chilly/soggy multi-pitch days). Our top picks are the Quechua Waterproof Mountain Jacket and the ultra-classic Black Diamond Stormline Stretch Rain Shell. To clean your waterproof wear wash with Nikwax Tech Wash, and then use Nikwax TX Direct Wash-In or Spray-On to restore water-resistance.

There really is nothing more miserable than a cold, wet day out – save yourself the suffering by visiting your local gear store to layer up.

Happy adventuring!