Layering is not complicated. It’s the process of adding and removing layers of clothing to keep your body comfortable in changing weather and temperature conditions.

Billions of dollars have been spent trying to optimize this process (and sell you stuff), but it’s really very simple: Put clothing on when you’re cold, take clothing off when you’re hot. Which clothing? That’s the rub, as they say. But don’t worry. We’ll walk you through what each layer is, how to layer, and when you’ll want it. Once you’re done here, check out our guides to the Best Base Layers, Best Puffer Jackets, Best Merino Wool, and Best Rain Jackets for more.

Updated February 2026: We’ve updated our advice based on new experiences, and put in a few new picks culled from all the gear we’ve tested in the last year.

Layering Basics

The key to layering is knowing what the layers are for and when to add and remove them. The high level overview looks like this:

• Base layer: The layer that touches your skin. These provide some warmth, but they’re primarily important for wicking sweat away from your skin. Being damp means being cold.
• Mid layer: The layer that’s—wait for it—in the middle. This is the layer where you actually start insulating, or trapping body heat. This is the key to the whole system and should usually be more than one layer (e.g., a lightweight fleece and a puffer jacket).
• Outer layer: The top layer is the waterproof, windproof layer that makes sure that nature does not steal all that precious heat you’ve retained in the mid layer. This is sometimes referred to as a “shell.”

While you won’t always be wearing all of these, especially when you’re exerting yourself while walking, running, et cetera, it’s usually worth carrying all three. If it’s cold, you can start with all three on and peel them off as you get warmer. When it’s hot you can do the opposite, pulling out a shell when you stop on a windy ridge. Obviously there are situations where you don’t need to carry all of them. Hiking the Florida trail in July? Skip the mid layer, ya lunatic.

Base Layers

Let’s start with underwear. Whether boxers, briefs, boxer briefs, or bras, go for materials that are going to help move moisture away from your skin. I have found merino wool to be ideal for underwear, but it’s worth trying different fabrics to find which works best for you.

Next comes what we generally think of as base layers: relatively tight-fitting but not overly restrictive pants and shirt with the dual purpose of insulating in cold weather and wicking sweat in hot. Again, there is a wide array of fabrics. If you opt for merino wool here, you benefit from wool’s natural ability to smooth out temperature variation across your skin, keeping you more evenly warm/cool (I call this temperature modulation).

There are also other options for fabric here, which includes Nuyarn. It has much of the benefits of merino (it’s usually more than half merino) but adds some nylon to provide extra strength and durability, as well as speeding up drying times. The latter can be important in very wet climates. In my experience, synthetic base layers do not perform as well at either insulation or moisture removal, though they will often dry faster, last longer, and are often cheaper.

Whatever you land on in your quest for the perfect base layer, generally avoid cotton. Cotton absorbs moisture like a sponge, becoming damp and leaving you wet and cold. If you want to be overly dramatic about it, there’s a saying: Cotton kills. It doesn’t really. I’ve done many a long hike, before I knew any better, wearing flannel shirts as mid layers and I am still here. But these days, with so many lighter, warmer fabrics available, there’s just no need to use cotton.

Terms:

• Wicking: This refers to the ability of a fabric to move moisture away from you skin. This is heavily used in marketing materials but in my experience isn’t what actually happens, even with merino wool. The important thing is to find a fabric that feels good against your skin and doesn’t completely wet out when you’re sweating.
• Weight: This refers to the fabric weight. Most base layers will be in the 160-grams-per-square-meter (lightweight) to 260-gsm range (heavyweight or expedition weight). Anything in between is mid-weight. Which one do you need? I’d tend toward the lightweight end of spectrum, but the difference is not huge. I find that more than weight, the tightness of the weave affects how well a base layer works and unfortunately there’s no standardized way to express that.

The Mid Layer

This is the workhorse layer of your layering system. The mid layer provides insulation to retain your body’s natural heat. The better your mid layer, the warmer you stay.

This layer also has probably the widest range of options, everything from ultra-lightweight Alpha 60 fleece to massively overstuffed down puffer jackets. Your best bet here is to have several mid layers, based on the expected temperature range of your adventures.

For example, in summer, hiking in the mountains, you might go with a very lightweight fleece (fleece has its own weight system, usually 100, 200, and 300 weight) or 250-gsm wool jacket for cooler moments, and a lightly filled puffer jacket (like REI’s 650 down jacket) should the weather turn nasty. In winter, your mid layers might be something like a 300-weight fleece jacket paired with a much warmer puffer.

Despite being WIRED’s official “merino guy,” I like fleece for a mid layer. Fleece will keep you warm even when damp, it’s easy to wring out when it’s wet, and it dries quickly. But what I really like is that fleece breathes well, allowing some of the heat to escape when you’re exerting yourself. That means you don’t have to be constantly putting your mid layer on and taking it off as your temp changes. The downside is that wind blows right through fleece. That’s where the third layer comes in.

There are also now some hybrid jackets that I like even better than straight fleece, like Ridge Merino’s Cloudripper fleece. Ridge has combined grid fleece with merino wool to give you the advantages of both, keeping the merino against your skin, but using grid fleece to improve ventilation and make the jacket much lighter. See my writeup in our merino wool guide for more on that jacket and why I recommend it.

Terms:

• Weight: This still refers to fabric weight, but mid layers will be in the 180-gsm, which is lightweight, to 300-gsm range for wool, 100-300 range for fleece, and puffer jackets with anywhere from 2.5 to 10 ounces of fill. (For our explanation on what fill means, check out our Down Fill Power guide.) The more mid layer options you have, the better you can pair your layers to your trip, which is why I tend to go for cheaper options here like REI’s house brand and Decathlon.

The Outer Layer or Shell

I like the term shell here because it captures exactly what this layer does. It provides a shell over the other layers to protect them from wind and rain. This layer has a tremendous range of options, from the ultralight and ultracheap Frogg Toggs (a thru-hiker favorite) to high tech “expedition” jackets that run to the thousands of dollars.

There is no one right option here, and again it’s worth experimenting to see what works for you. We have a whole guide to rain jackets to help you figure out the right one for you. It helps to be realistic about what you’re doing. If you’re mountaineering or live in a very wet climate, by all means invest in something heavy-duty. If you’re just looking to shed the occasional shower and stay warm atop those high passes, you might not need something as heavy-duty.

I know it seems crazy, but grab a set of Frogg Toggs and go for a walk around your neighborhood in the rain and see what they’re like. If you’re miserable, send them back to Amazon and try some of the cheaper rain jackets we like.

My experience has been that a jacket can be waterproof or it can be breathable, but it cannot be both at the same time. I have a couple of shell jackets to use, depending on the scenario. For day hikes I tend to bring along something ultralight like Patagonia’s Houdini jacket, which is primarily a wind jacket, though it will repel some rain (not much though).

If I’m going for a longer period of time or expect rain, I bring a sil-nylon jacket of some sort. Sil-nylon is 100 percent waterproof but doesn’t breathe at all, so look for jackets with pit zips and other means to ventilate. I recently picked up a poncho like the one I had when I was backpacking as a kid in the 1980s. My hope is that it might ventilate better than a jacket, but I haven’t tested it yet.

Putting It All Together

I find it easiest to think of layer in terms of use cases. Here are a few scenarios for different environments and seasons to get you started in figuring a layering system that works for your adventures.

Keep in mind that environmental conditions aren’t the only consideration. Think about how hard you’ll be exerting yourself and how your body does under these conditions. If you’re a perpetually cold person, bring heavier mid layers. If you tend to run hot, you might be able to get away with less. That said, here are some common hiking/backpacking situations and some sample layers to get you through them.

Summer mountain backpacking layers: Grab a lightweight merino base layer like Smartwool’s classic all-season merino and pair it with a midweight fleece jacket like the Ridge Cloudripper merino grid fleece or ultralight down jacket like Decathlon’s Simond MT100. Top that off with a waterproof rain jacket. If you’re day hiking, you can probably go with just one mid layer.

Fall backpacking at lower elevations: Start with a heavier base layer, like this midweight option from Icebreaker, then add a midweight fleece jacket and midweight down jacket like our favorite from Outdoor Vitals. For a shell you might want something heavier like the Arc’teryx Beta.

Spring in the desert: Warm days, cold nights—the trickiest layering situation you’ll encounter. I’d go with a midweight merino top and lightweight merino pants for the baselayer, along with a midweight down jacket and a lightweight fleece. For the shell, you could probably get away with a wind shell like the Patagonia Houdini and maybe a poncho for rain.

Spring in Florida: Lightweight merino T-shirt. Flip flops. Ah, Florida.

Got layering questions? Drop them in comments below and we’ll do our best to test and answer them in future updates to this guide.