We’ve all been there. You’re scrolling on Amazon, wondering how to choose base layers.

Even though Christmas is over, we’re still in the full swing of winter.  For those of us in southern California, it’s a little hard to believe cold weather exists sometimes. But for the rest of you and those who like to go on outdoor adventures, you’re seriously thinking about investing in new cold weather gear. After all, it’s about that time of the year again. In this article, we’re going to run you through everything you need to know about how to choose base layers. Believe it or not, there are a lot of variables to consider.

What are Base Layers?

If you haven’t really traveled in cold weather before, you might not know how to choose base layers or even what base layers are (also known as thermals or long underwear). That’s okay. We’re here to walk you through it all. These are layers you wear under your clothing which help to retain your body’s natural heat and keep heat from escaping during cold weather. When it comes to how to choose the right base layers, you will want to consider which types of material you like best, the price point of the items, the length of the base layers, and remember to choose based on which season you’re traveling in. For example, you will need thicker thermals traveling in winter than in fall.

Questions to Ask Yourself Before Beginning Your Search:

If you need a starting place, then it will help you to begin by considering a couple of questions. When you’re wondering how to choose base layers, here are some questions to ask yourself. They will point you in the right direction.

How much do you want to spend?

Knowing your budget will be key to finding how to choose base layers. Whether you are looking for an inexpensive thermal set or are willing to spend a little more, knowing your budget will help narrow down your options. We suggest approaching this with a price limit in mind. That way, you will be able to knock off all the items that are out of your price range much faster and, subsequently, locate your perfect winter wear that much faster as well.

What Season Are You Traveling In?

Most of the jackets on our list are geared towards cold winter weather. Unless you're hiking in extreme weather conditions or an incredibly difficult trail, you won't need the extra weight of extreme bulk. The best base layers offer great insulation properties, are durable, and lightweight. This is important when it comes how to choose base layers.

How Long Are You Traveling For?

Make sure you have base layers that are good quality. If you’re investing your money in this travel item, you want one that will hold up to the tests of time and the elements. Factor in how long you are traveling for and how you will keep your layers clean while you’re on the go.

What Length Do You Want?

If you’re traveling somewhere very cold like Europe in say December (oddly specific, we know), consider investing in long underwear. Take it from people who have been there and done that. You’re going to appreciate having a long down coat that will cover as much as possible.  It gets so cold, we swear you wouldn’t mind looking like the Michelin tire baby if that’s what it takes to be warm. Some base layers are shorter on the legs in an athletic legging fashion. We highly recommend choosing the longer layers that completely cover your legs and arms. This will keep you warmer and avoid any lumpiness in layers that you may come across otherwise. 

Here's How to Choose Base Layers

Do you want to layer well and stay warm during your winter travels? Knowing how to choose base layers is important. When it comes to making the decision, three main factors come into play. The fabric is the most important part. Whether you opt for a synthetic material or a natural one, you want fabric that wicks moisture off of your skin. 

Next, comes the weight of the material. How heavy or light do you want it to be? When it comes to layering, choosing thin thermals is often the best way to go. You can eliminate the bulk while still staying as warm as possible. Choose from lightweight, midweight, and heavyweight styles. The final factor deals with the fit. Since wicking fabric has to be touching your skin to work well, you should choose base layers that fit you snugly. 

Synthetic or Regular Fabric?

This is the first thing to consider when you are it comes to how to choose base layers. For its weight, natural down is warmer and compresses better. However, when it gets wet, it will lose its loft (its insulation). Synthetic fabric is often heavier than natural fabric. While it offers just about the same thickness and warmth, it does not compress as well when it comes to packing. However, even wet synthetic material will retain most of its insulating capabilities. So, even if your synthetic thermal fabric gets a little wet, you won’t be suffering in the cold.

Moving on to durability, synthetic materials (with the exception of wool) tends to last longer. What do we mean by this? Synthetic fabric also allows for more breathability. This brings us to abrasion. Synthetic thermals are much more durable in this sense of the word. 

Synthetic Materials

When it comes to how to choose base layers, many travelers get stuck between synthetic and natural materials. In this section, we will break down the types of synthetic materials and their purposes so you get a better idea of how they perform. The most popular type of synthetic fabric for thermals is polyester. It is also common to see nylon, polypropylene, rayon, or a blend of the above fabrics. 

Synthetics offer a super dry wear. This means that even if you are sweating a lot, the moisture wicking properties will keep you cool and dry. They are also more durable than natural fabrics. While no type of base layer is invincible, they are much less prone to getting snagged or torn easily. Finally, they work very well in the odor department. Many synthetics come with a finish that wards off odor-causing bacteria. If you are going to go multiple days without washing your clothes, this will help loads.

Merino Wool

While most people think of merino wool as an itchy fabric you can't stand to wear, those days are long gone. Merino wool is so different from traditional wool, thanks to its ultrafine fibers. Besides, it is very easy to blend wool with other fabrics (e.g spandex) tomake it much more flexible. Merino wool wicks moisture well, is moderately durable, and helps you to stay odor free.


If you're wondering how to choose base layers, remember that comfort is key. We are big fans of silk thermals. With this said, it's a viable option for low-key activities. If you are exploring a new city in cold weather or going on a short hike, it works well. With silk layers, you can expect moderate wicking, suppleness, and unfortunately, odor retention. Since silk is not naturally odor resistant or antimicrobial, it is likely that it will have to be laundered every time you wear it.

The Weight of Your Base Layers

You don't have to worry too much about this part but it is still important to take into consideration. Are you always the “cold” person when you are traveling? If so, you should consider investing in the heavyweight thermal styles. When it comes to long underwear, there are three weight options: lightweight, midweight, and heavyweight. Some brands really try to push the lightweight aspect, opting for names like featherweight and ultra lightweight.

 Here, we're going to keep it sweet and simple. Lightweight thermals are for moderate to cool temperatures, midweight is for cold temperatures, and heavyweight is for below freezing weather. It is important to keep in mind that part of your thermal's job is also moisture management. The material needs to keep you cool and dry. While heavy base layers can add some warmth, ultimately it is the insulating middle layer that keeps most of your body's heat retention. 

The Fit of Your Base Layers

How your base layers fit you is so important. As we mentioned earlier, the moisture wicking properties of your base layers will not work unless the fabric is touching your skin. Consequently, your base layers must fit snugly in order to do their job. We have found that we are most comfortable in stretchy, snug fitting fabric. Don't simply rely on styles that label themselves as an “athletic fit.” 

Try the thermals on if you can. If you are ordering online, make sure to check the size chart and know your measurements. While some people prefer a loose fit, that means you lose insulation properties. While they think they are getting better air circulation and cooling, you also sacrifice wicking efficiency. Furthermore, warm base layers spread out over a wider area is cooling when evaporation takes place. 

Wrapping it Up: How to Choose Base Layers

We hope that our research has given you a little insight on how to choose base layers. As with most pieces of outdoor apparel, the process begins with identifying the elements you’ll be in and the weather you anticipate to face. Other important factors to consider include your budget and how long you are planning to travel for.

When it comes to how to choose base layers, work your way through these questions. It is also important to keep in mind that you get what you pay for. Generally speaking, the established brand names will offer the better quality. When it comes to travel gear, you want to make sure you invest in a quality product that is going to hold up. There are plenty of great, fashionable finds out there. While every type of thermal has its pros and cons, we know you are well on your way to finding your best fit. Happy travels!

Related Article: Best Thermal Underwear Styles For Men And Women