Let’s face it: Staying warm in cold weather isn’t easy.
With dozens of different fabrics to choose from when packing for your next winter hiking trip, figuring out which one is right for your needs can be overwhelming.
The good news is that finding the warmest material for your winter escapades doesn’t have to be impossible. In this article, we’ll give you the lowdown on the various options out there so you can be prepared for whatever conditions you face in the mountains.
Table of Contents
1. Merino Wool
Often lauded as a miracle textile, merino wool is a relative newcomer to the world of outdoor gear that’s quickly taken the industry by storm.
Made from natural fibers sourced from merino sheep, merino is simply another kind of wool. However, unlike the scratchy wool you’d find on that Christmas sweater that your granny knit, merino fibers aren’t itchy and they offer outstanding next-to-skin comfort.
Merino fibers are thinner and softer than those in standard wool, which makes them soft to the touch. While they aren’t necessarily as soft as cashmere or fur, merino wool garments are popular because they don’t itch or smell, and they’re a great moisture-wicking option.
Merino wool is sold by many companies, like Smartwool, Darn Tough, Icebreaker, and Ibex. Moreover, a layer of merino is sold in different “weights,” measured in grams. So, 60g merino garments are lightweight base layers while a 120g layer is a beefier option that’s ideal for cold weather instead of a cotton shirt or flannel.
Irrespective of weight, this kind of wool is excellent in moisture-wicking garments, like base layers, long underwear, and socks.
The downside? It’s really expensive and it doesn’t have the best warmth-to-weight ratio when compared to alternatives like down.
Crafted from polyester fibers, fleece is a synthetic fabric with a fuzzy texture. Found in everything from sweaters and jackets to socks and hats, fleece is an ideal mid-layer for damp environments.
That’s because fleece is great at keeping you warm even in the snow. Although it’s not very wind-resistant, it is comfortable, quick-drying, and usually quite affordable in price.
Most fleece sweaters, mid layers, and base layers are sold in different weights (in grams) so you can decide which thickness is best to keep you warm. For example, most companies sell fleece fabric in the following weights:
- <100g: Micro/ultralight
- 100-200g: Lightweight
- 200- 300g: Mid-weight
- 300+g: Heavyweight
Like all materials, fleece has its downsides. In particular, it’s heavy and bulky when compared to synthetic fill, it’s not the most effective moisture-wicking textile, and it’s made from non-eco-friendly polyester.
Out of all the warm fabrics for winter conditions, down often reigns supreme in dry environments.
Made from the clusters of down plumes from birds, like geese or ducks, down is a natural fiber that’s popular for its superb warmth-to-weight ratio. It’s one of the warmest fabrics and it’s used for mid-layers and other insulating clothing like coats, hats, and gloves. That’s because it’s lightweight, super packable, and oh-so-comfortable.
Down quality is assessed using a metric known as “down fill,” which indicates the volume, in cubic inches, of 1oz of down. While this metric is a bit too techy to get into here, higher fill power down insulation (e.g., 900 fill) is generally better quality than lower fill (e.g., 450 fill).
The drawback to down insulation is that it’s of zero use to you when it’s wet. When damp, down plumes clump together, depriving them of the “loft” that makes them such good insulators when dry. As such, down is not something you want to be wearing in high-moisture environments. High-quality down is also very expensive and is not allergy-friendly.
But, if you want some truly exceptional clothing to keep you toasty in cold and dry conditions, you’d be hard-pressed to find anything better than down.
4. Synthetic Insulation
An alternative to down fill, synthetic insulation is a relatively new product that’s excellent for use as an insulating material in a winter jacket, coat, top, or other warmth-focused clothing like vests and hooded sweaters.
Unlike down, which is a natural fiber, synthetic insulation, is well, a synthetic fiber. It’s made from thin filaments of polyester (or other similar materials) that are wound up and bunched together to mimic down’s insulating abilities. The plus side is that synthetic clothing is one of the warmest fabrics when wet, unlike down.
These days, there are many different brand names for synthetic fill, including:
- The North Face Thermoball
- PrimaLoft Gold/Eco/Silver
- 3M Thinsulate
- Columbia Omni-Heat
- Arc’teryx Coreloft
Regardless of what it’s called, a layer made from synthetic fill will be rated by a metric called “gram weight,” which is expressed in grams per square meter. Simply put, a layer with a higher gram weight, such as 120g, will be warmer than a layer with a lower gram weight, like 60g.
You’ll generally find this kind of material used in gear such as jackets, vests, and gloves as it’s a good insulator in wet environments.
While synthetics have a lower warmth-to-weight ratio than down, they’re a more affordable choice than down for any clothing layering system.
Originally developed for use in objects such as parachutes during World War II, nylon is a synthetic fabric that’s renowned for its strength and lightweight.
Although there aren’t any super popular nylon brand names out there, it’s most commonly used to make rain jackets, rain pants, and other outer layers that protect your body from moisture and foul weather.
Even though nylon doesn’t provide much insulation on its own, it is a lightweight solution for staying dry. It’s a highly durable fabric that can be treated with DWR (durable water repellent) or combined with a special membrane to make it fully waterproof for winter use.
Plus, nylon is pretty darn cheap these days, so it’s a must-have for any layering system.
An oldie but a goodie, silk is a time-honored natural fabric that’s derived from a fiber produced by certain insects, such as the silkworm.
Although it was most popular back in the days of George Mallory and the early Mount Everest climbers, silk is a super comfortable layer to wear on any fall or winter trip. This is especially true when a silk layer is coupled with a wool sweater, which can trap in extra body heat in cold temps.
While silk is very expensive, it’s lightweight and offers excellent next-to-skin comfort. It’s also a highly breathable fabric, so it may be a nice choice if you’re in need of some new base layers.
The Verdict: What Are The Best Warm Fabrics For Winter?
At the end of the day, there’s no single fabric that’s better than all others in terms of warmth in the winter months. Regardless of which textile you opt for, the key is that you make sure to choose the ideal material for your needs.
We hope that this guide helped you pick out the best material to wear when adventuring in winter conditions. If you found your next go-to clothing to wear to help keep your body warm, let us know in the comments below and don’t forget to share this article so your friends can keep warm, too!