Smartwool Merino Sport Ultra Light Hoodie

A basic, lightweight, hooded, nylon windshirt with a partial, light wool lining in the hood. There’s not a lot of wool-warmth here, and no real rain protection, limiting the useful weather window, but it's well made and does its small job well. Best for light and fast summer trail runs or day hikes when there is wind but no rain in the forecast.

Sometimes a simple windshirt is the right choice for a day outing. It’s a warm summer day, no rain in the forecast, perfect for a trail run or power hike. So you set out for the summit in shorts and a t-shirt, with a small fanny pack with a water bottle and some snacks. You work up a massive sweat as the trail winds up steeply through the forest. By the time you reach treeline, the temperature has dropped with altitude and you notice there’s a little breeze, but, no problem, you’re still running hot by virtue of forward motion.

But as you approach the summit, you are more exposed to the wind and when you stop to take in the view you start to feel downright cold as the sweat evaporates. If you’re smart, you’ve got an extra layer in that little fanny pack (or runner’s vest). And if it’s really windy, it might be nice if that extra layer had a hood, and some pockets to get your hands out of the wind as well. That’s the rather narrow niche that Smartwool’s Merino Sport Ultra Light Hoodie fits into.

Materials, Design, and Detail

Smartwool’s web page description might be a little misleading:

“Main Body: 100% Recycled Nylon; Trim, Lining & Inside Hood: 54% Merino Wool, 46% Polyester”

That might be taken to imply that this is a nylon shell with some kind of wool lining. It is not. There are two 150 weight, 46/54% knit poly/wool blend panels inside the hood and a pair of extended underarm vents of the same material—that’s it. This may help keep the head, and I suppose underarms, a bit warmer in a cold wind, but otherwise there is no insulation. The panels have small perforations to enhance breathability.

The nylon shell is a tightly woven, very light ripstop, with an exterior DWR finish for water repellency but no interior lining, coating or waterproof /breathable membrane. It's good keeping the wind out and the DWR will get you through some light rain, but not a whole lot more moisture than that before it starts wicking through.

Smartwool has added some thoughtful details that make it a little more useful than a classic no-frills wind shirt. These include:

• The aforementioned hood liner for a tad bit more warmth in a summit wind

  

• An elastic cinch on the hood to draw it close to the back of the head. With the jacket zipped up to the chin, the hood will stay up even in a headwind, even though there is no drawstring to snug around the face.

  

• Similar elastic cinches on the wrist cuffs

  

• Reflective accents on the inside of the wrists (these are both too small and in the wrong place to be very effective in alerting approaching drivers on a road run, but in an updated version Smartwool has moved these to the wrist cuffs where they might be a little more visible)
• Generous mesh wool blend underarm vents.  

  

• Additional venting via open/tacked shoulder seams

  

• DWR finish for water repellency. I splashed some water on it after I had used it for a few weeks. Some drops beaded up nicely, but others started to spread and wick into the fabric. I don’t think these coatings wear very well in general, although they can be refreshed. On a recent hike I weathered some brief, light rain but switched to a more waterproof shell when the going got wet.

  

• Zip-up handwarmer pockets, good for stashing gloves and hat after warming up, and roomy enough for a point-and-shoot camera or big-screen cell phone.
• Inside zipper pull on the right hand pocket so it doubles as a stow-sack. The windshirt can also be compressed to a much smaller size.

  

Fit, style, and comfort

The hoodie is available in Men's sizes S to XXL and Women's XS to XL. The size men's L is a bit short in the body and sleeves on my skinny frame, but that’s typical for most outdoor gear that only comes in canonical sizes.  It should be true to size for people with more conventional proportions. The size L weighs 158 g / 5.6 oz.; Smartwool’s weight of 144 g / 5.1 oz is presumably for a size M. 

When it comes to color choices, Smartwool is playing it chill. The Military Olive version that was sent to me is about the right color to blend into the late summer Norwegian tundra, but with yellow accents for style. The other choices are black/black and navy/royal blue. Smartwool also offers a women’s version in navy, rose pink, or powder blue, plus hoodless versions and a vest for both genders.

On cool morning runs, the ventilation prevents moisture buildup in the body, but I have had the sleeves get damp on the inside, maybe a sign that’s it’s time to take the outer layer off.

It's machine washable, cold/gentle.

Wind and Weather Protection

The tightly woven nylon offers excellent protection against summit winds, and the DWR finish (while it lasts) will repel brief, light rain or fog, but something more waterproof would be needed for more continuous wet conditions. It should serve well as a summer to early autumn windstopper, but as temperatures dip below freezing I would want something a little beefier.

Best Use

As noted above, this hoodie is a good choice for light and fast hikes or runs in cool to around freezing temperatures when there is wind but little rain in the forecast. The wool-lined hood is a nice touch that might also be welcome in a waterproof/breathable or fully waterproof version. The light weight and compact size make it a good fit in a trail running vest.

Background

I have used this hoodie on my body or in a pack on numerous short to medium trail runs near home, a few longer day hikes, and an early summer ski mountaineering outing or two. More recently it was a great companion on a three-day, above-treeline hike in continuously windy and chilly conditions in Norway's Rondane mountains, when I wore it pretty much all day from camp to camp. It is one of about five windshirts and light jackets that I have in current use, and of many more in a lifetime of outdoor activities.