REI Midweight Half Zip Base Layer Review

Bottom Line

If you’re only going to buy one base layer, the REI Midweight Half Zip is a great option. No base layer can do it all, but this one comes close. It may be a little warm for an aerobic activity, but it’s fairly breathable and dries surprisingly fast. It also has a zippered neck for dumping excess heat.

We tested this base layer in a controlled setting as well as hiking and backpacking in the Rocky Mountains, and we found it to be one of the most versatile options on our list of the best base layers. On top of that, it packs an incredible amount of value into a very affordable price point.

Because it is on the warmer side, there are better options we would recommend if you’re looking for something to just take the chill away during a fall run in the mountains or a spring ski tour.

Comfort

The REI Midweight Half Zip is a super comfortable base layer with its ultra-soft polyester and snug yet flexible fit. The brushed interior feels cozy against the skin, and the neck zipper allows you to dial in your preferred fit throughout the day, whether you need to dump excess heat or want to bundle up and keep your neck warm.

The seams of this top are completely unnoticeable against the skin, and the shoulder seams are rolled forward to stay out of the way of pack straps. We also love the added bonus of the thumb loops. They’re thick and durable and help with layering.

One of the unique benefits of the REI Midweight Half Zip is its ability to be used as a base layer or a mid-layer. It is snug enough to slide easily underneath a fleece but loose enough to layer over a slim-fitting base layer. It stays in place and doesn’t bunch up underneath multiple layers.

Overall, the REI Midweight Half Zip is supremely comfortable and gains a few extra versatility points in our book.

Warmth

The REI Midweight Half Zip has a fabric weight of 220g/ms, so it’s definitely a bit on the heavy side. However, this is balanced by the option to open up the neck zipper for a little more airflow. On the other hand, when the zipper is all the way up, it provides extra warmth by protecting vital arteries from wind chill.

This top has excellent moisture-wicking capabilities. The synthetic fibers effectively wick moisture away from your body and towards the outdoor layers of the garment, speeding up drying time and keeping you warm and comfortable in the process.

Warmth, however, may not always be what you’re going for. The REI Midweight Half Zip is a bit too burly for high-output activities. If worn as a running base layer in late spring or early fall, you’ll likely be soaked in sweat and wishing for something a bit lighter.

Breathability

The REI Midweight Half Zip is surprisingly breathable for a base layer on the warmer side of the spectrum. We sprayed the same amount of water on all of our base layers and then tested how quickly they dried, and this one performed comparable to lighter, more active base layers. However, much of that had to do with its moisture-wicking capabilities, which go hand in hand with breathability.

As far as perceived breathability goes when we actually wore the base layer and got outside for a hike, it has more to do with the features than the fabric itself. With the neck zipped up, the REI layer can feel a little stuffy. We didn’t feel much of a cooling breeze when the wind wasn’t blowing. Unzipping the neck makes a world of difference, allowing a lot of heat and moisture to escape and creating a wind tunnel through the layer. What the REI Half Zip lacks in fabric breathability, it makes up for with the zipper.

Versatility

We love a base layer that can become our go-to all year round. The REI Midweight Half Zip is a great weight for most of the year and provides a few extra features that take it the extra mile.

If you’re hiking through the Mojave desert or in the humid swamps of Florida, this REI base layer may struggle to find its way into your laying system during the hotter months. However, in mountain climates like Colorado, we have no problem stuffing it into our pack any time of the year. During the frigid months, it works great as a heavy base layer for hitting up the ski mountain. For spring and summer backpacking trips, we use it as a passive layer for sleeping and camp lounging.

Its versatility is due to added features like the neck zipper and the thumbholes. The neck zipper extends its usability to warmer climates, allowing you to get more airflow and shed some heat buildup. We also love the thumbholes and consider them a point in versatility. They make the top more comfortable, make it easier to layer, and give it more coverage.

Style

On top of its practicality, the REI Midweight Half Zip looks great. REI offers this top in seven different colorways, which isn’t a ton, but it’s plenty for most people to find one they like.

Something about a neck zipper just looks great. It drastically changes the layer’s appearance from a turtleneck to a more relaxed look. It also has a fit that is not too loose or tight. It’s flattering yet relaxed.

The REI Midweight Half Zip is one of our go-to’s when we know we’re headed out for drinks with friends or a business dinner immediately after a hike.

Should You Buy the REI Midweight Half Zip?

The REI Midweight Half Zip could be your “one layer does most” base layer. It keeps you plenty warm enough in the winter months, and the half zipper is a lifesaver when things warm up and you need a cooling breeze. It’s also equally comfortable as a base layer as it is as a mid-layer.

If you’re sensitive to certain fabrics, this top is one of the most comfortable on our list. The brushed interior feels ultra-soft, and the flat seams are unnoticeable.

If you’ve already got a warm option in your base layer quiver, and you’re looking for something to keep you warm and dry on runs, long ski tours, or summer months, the REI Midweight Half Zip might be a little too toasty.

What Other Base Layers Should You Consider?

Arc’teryx Rho Heavyweight Neck Zip Review: The Arc’teryx takes a lot of the pros of the REI Midweight Half Zip to the next level. It’s warmer, more comfortable, and works as a true mid-layer. The downside is it is less versatile and way too warm for summer months.

Patagonia Capilene Midweight Crew Review: The Capilene is synthetic like the REI Midweight Half Zip, but it truly works all year round. It easily fits into any layering system at any time of year, although it needs to be paired with a mid-layer in the winter. 

Smartwool Classic Thermal: If you’re looking for a similar base layer but prefer wool over synthetics, the Smartwool Classic Thermal might be your best bet. Although it doesn’t have a zipper or thumbholes, it is comparable in warmth and breathability.