Merrell Thermo Chill 2 Mid Review

The Merrell Thermo Chill 2 Mid is a friendly, unassuming modern winter boot that cruises on frigid trails as easily as it crosses frozen parking lots. It's great for anyone who wants a lightweight waterproof boot with enough insulation to keep their feet warm while on the go.

Warmth

The Thermo Chill 2 Mid was surprisingly warm for its light weight, short height, and relatively thin 200 grams of insulation. This insulated hiker isn't as warm as the taller, heavier boots we tested, but it easily kept us warm while hiking in six inches of snow. We even stood in a frigid little stream that took a couple of minutes to transfer just the hint of a chill.

Merrell uses its M-Select WARM synthetic insulation, which uses reflective micro-spaces to help trap body heat. Compared to other boots, it did its job well, despite being one of the lightest boots we tested. We believe it is best suited for use on the go when hiking on cold pre-snow days and for hiking urban trails packed with snow and patches of ice and slush. Despite its warmth, the low height does impact its ability to maintain heat — taller boots tended to run warmer.

Weather Protection

While taller boots tend to run warmer, they also tend to provide more protection from adverse weather conditions. While we have tested winter boots with lower maximum puddle depths than the Thermo Chill 2 Mid's 5.25 inches before flooding, it's not hard to soak your socks if you try to cross deep puddles in these boots.

When it comes to keeping cold snow away from your ankles and legs, the slightly higher 7.5-inch shaft height does well in light powder snow. Because pant legs easily cover these boots, we could still hike for a quite a while before our pants legs became saturated and transferred moisture to our socks that rose over the tops of the boots. As for waterproofing, these are the real deal: No leaks, even after standing in 5 inches of cold water for several minutes.

Comfort and Fit

Like the previous version, the Merrell Thermo Chill 2 Mid are still some of the most comfortable winter boots we've tested. They don't require a break-in period — but they do get even better as the forefoot gains flexibility after just a few miles. In addition to the cushy insulation, Merrell lines this little boot with a 100% recycled fleece lining.

Unlike many winter boots, the Thermo Chill laces extend down over the forefoot, letting you customize the fit to your liking. This is particularly handy if you're on a long downhill stretch and want to snug your foot down to the footbed so your toes don't hit the ends. Overall, Merrell nailed the design here — it really does feel and ride like a good, non-insulated hiking boot.

Traction

One of the biggest differences between the original Thermo Chill Mid and the new Thermo Chill 2 Mid is the tread design. The previous version used a very tall, very aggressive lug pattern. It worked great off-trail and in deep snow, but the old tread design, which had few points of contact with the ground, wasn't optimized for traction on pure ice.

The new pattern still uses a relatively soft sticky rubber compound, but Merrell significantly changed the tread pattern to reduce tread depth and create more points of contact with icy surfaces. The result is a reduction in mixed debris traction — think dirt, leaves, mixed snow, sand — and an increase in traction on ice. Better yet, the new tread design picks up very little dirt, mud, or snow and self-cleans well. If you're using these boots to walk around town or run errands in and out of stores, the soles are easy to stomp off before entering a store or restaurant. Overall, we didn't miss the slight drop in dry-ground traction . . . but we very much appreciate the slick surface gains.

Quality of Construction

The overall Thermo Chill Mid build quality is good — certainly on par with its relatively affordable price point. The front bumper toe cap is double-stitched, but most of the other upper stitching is single-row stitched, which means it's simply not as tough as double-row stitched sections. The previous version featured double-row stitching, so this downgrade is a bit annoying. However, most winter boots don't smash through brush and debris like well-used hiking boots, so this single stitching may turn out all right for most people.

Despite the change in upper stitching, Merrell made a huge upgrade to the eyelets. Instead of tight nylon fabric eyelets that created excess friction and is a common wear point that we see fail in many boots, the new eyelets are larger leather loops. They should result in less friction and should prove more durable over time.

Should You Buy the Merrell Thermo Chill 2 Mid?

If you like to hike snow-packed trails or walk your dog among snowy sidewalks and slushy streets, the Thermo Chill 2 Mid is fantastic for cruising in comfort. As long as the snow isn't deeper than six inches, it outperforms larger, clunkier boots. With its modest amount of insulation and lower height, it's not the warmest option for truly frigid temperatures, and it's best used for those who are keeping their blood flowing by walking or hiking. The waterproofing is excellent, making it good for rainy day hikes and afternoon transitions where light fluffy snow turns heavy, wet, and slushy. If you need to step through deep puddles or navigate big snow drifts, this isn't the boot for you. But if you need a cold weather hiker or nimble snow boots for shoveling the driveway or running errands around town in winter, these will likely work for you as well as they have for us.

What Other Winter Boots Should You Consider?