The Macpac Interwool Mountain Warmth baselayer is a hybrid, consisting of a textured wool layer next to skin, a polyester outer layer to wick moisture away, and a Lycra component for stretch. As the name implies, it is designed for cool and cold weather high output activities. The long sleeved zip-top weighs 10.5 ounces in size Large.
On sunny above-freezing winter days, the Mountain Warmth top as an outer layer was comfortable while hiking, skiing, or snowshoeing. (Photo by Rick Hagar)
Features include a 10-inch front zipper, raglan sleeves, hidden elastic thumb loops, stand up collar, underarm and side stretch panels, and a zippered pocket on the left cuff. The top is exceptionally well made using high quality fabrics, and fits well. The outside surface is smooth, so other clothing easily slides over it.
There is a concealed thumb hole inside the cuff (left) to assist with putting the top on, although it’s hardly needed. The small zippered pocket on the left cuff (right) is a curiosity. I am not sure what it is intended for, and I could not find a good use for it.
While the wool and Lycra content plus a zipper add a bit of weight to this garment, the weight is offset by its superb performance in cool and cold weather when worn as either a baselayer or outer layer. I wore it 43 days while testing it in a variety of activities and conditions. The result is that the Mountain Warmth top is now a part of my cool/cold weather clothing system, and I wear it so much that I have a hard time finding a chance to launder it (and it doesn’t develop any odors to remind me of the need)!
The inside surface of the Macpac Mountain Warmth top is textured to trap more air for insulation. The left side is a stretch underarm panel; note the different fabric orientation to improve articulation.
On sunny winter days with temperatures above freezing, I was able to wear the top as an outer layer while actively hiking in temperatures down to freezing. On my fall outings I discovered its broad comfort range, feeling comfortable from freezing morning temperatures to afternoon temperatures up to about 60 °F. It was also remarkably dry, more so than a pure merino wool baselayer.
In sub-freezing temperatures, I layered over it as needed for warmth, but frequently wore just a wind shirt over it. On winter backpacking trips in the southern Utah canyon country and snow camping in igloos we built, I wore the Mountain Warmth baselayer during the entire trip, adding layers over it as needed.
I also found the Mountain Warmth top to be quite durable. I wore it while hiking through brush on many occasions, and it has picked up very few snags. It’s more durable than many polyester baselayers I have worn.
Overall, for cold weather outdoor activities and camping, the Macpac Mountain Warmth long sleeve zip top is a remarkable baselayer providing plenty of warmth, dryness, and comfort. It’s a superb top for aerobic activities in cold weather, by itself or with a breathable windshirt over it.
Features and Specifications
- Manufacturer: Macpac (http://www.macpac.co.nz/)
- Fabric: Interwool Stretch – 22% merino wool, 66% polyester, 12% Lycra; 180 g/m2
- Sizes: S, M, L, XL
- Features:10-inch front zipper, raglan sleeves, hidden elastic thumb loops, high collar, underarm and side stretch panels, zippered pocket on left cuff
- Weight: Measured weight size Large 10.5 oz (298 g); manufacturer specification 10 oz (283 g)
- MSRP: $100 US