Theory of Windshirts for a returning backpacker

It’s for wearing over whatever you wear on the move.

A wind shirt is a light nylon jacket that prevents convective heat loss.  They used to be called windbreakers, though in that day they were usually lined.

Most base layer shirts that you would hike in offer little protection to convective heat loss due to the wind so a windshirt is used.  If you are already wearing a shirt that is wind resistant, such as a tightly woven nylon shirt they are not as useful.

Your rain jacket can perform the same function and many advocate using it instead of a wind shirt to save weight by not having to carry a separate wind shell, however rain jackets don’t berate nearly as well and are easy to overheat in.  I can’t hike very hard in a rain shell without overheating but I can hike pretty hard in a windshirt without overheating.

The gold standard wind shirt was the Patagonia Houdini until they changed the fabric to be less breathable in about 2012.  Nowadays I would think the Arctrex Squamish tests the best but it isn’t cheap.

I will add that some backpackers find them more useful than others.  I have found I use it infrequently in the southeast but find it invaluable out west.   I was also surprised that I didn’t wear mine much in Alaska this year considering how much I have used it on trips to the Sierras and Rockies.

I only use one in the winter here in the SE.

“Is this thing intended to go over your insulation layer (the high loft Jacket?) If so, I’m going to have to find a bigger wind jacket.”

Not really, since you won’t likely be “on the move” while wearing a high loft jacket, as Stephen said. But you do want to make sure you can wear a base layer under it and not feel too constricted, at the very least.

Personally I use mine <b>all the time</b>, typically over a base layer or two. When I stop moving, I’ll throw a warmer layer over it if it’s chilly. When not on the trail, it’s my preferred layer I go running in. I just think of it as a tightly woven shirt, that’s all.

I will offer that not all wind shirts are created equal, and all the fabrics used peform differently toward reducing convective heat loss (they don’t actually stop it.) There are some very detailed and thorough articles and discussions in BPL on windshirts, and I recommend digging into them for more perspective.

So have fun trying it out, and see how it might work (and not work) for you.

And welcome back! The base gear has become a LOT lighter that it was in the year 2000, that’s for sure.

I like wearing the “microfiber” windshirts made by Badger for golfing. These shirts aren’t for big down puffy jackets; instead, I use mine with a fleece hoodie. I think this combination is more durable, versatile, lighter, and cheaper than many ultralight puffy jackets. I’ve broken out big cash for a puffy jacket, and I wasn’t impressed; it was light but flimsy, yet more durable jackets become heavy very fast. In the end, all jackets will lack the versatility of a layered option such as a hoodie / windshirt combo.

To test it out to see if it works for you buy (or dig out of your closet) an old dress or casual shirt (not cotton) wear it over your base layer (and mid layer if required) and go for a hike. Basically a windshirt is just a tight weave nylon or polyester shirt (sometimes with a hood and often with a DWR coating) worn over other layers that stops most of the wind but still breathes. As already stated it’s usefulness varies a great deal on climate and personal needs.

I find it works for me in Atlantic Canada where I get a chill from the wind, but wet out puffies if I wear them while moving.

Everything above is true. But to me the description of a windshirt is that it is one of the most versatile pieces of gear I have. It’s a layer you can use so many ways:

• In general, for 3 oz that packs away to almost nothing, it’s the perfect layer for when you need a little more.
• As described, it is a breathable layer for when you’re on the move.
• It’s a water-resistant layer that still breathes — depending on where you’ll be and what other equipment you have, this may be the only upper-body rain layer you need.
• If you take a break from hiking and don’t want to get too cooled off the windshirt can be just the right amount to pull on.
• In camp in the summer it might be the only “at-rest” layer you need to retain a little extra warmth on a mild evening.
• Or, in camp on cooler nights I put on the down sweater and if it’s windy that can cut through the down so I can layer the windshirt with the down sweater to cut the wind and stay warm.
• Typically I sleep wearing my day shirt and then I’ll use my down sweater as part of my pillow, and if it’s really cold I’ll pull out the down sweater but if it’s just a little cold for the quilt then I can pull on the windshirt for an extra layer of warmth to sleep in while leaving my pillow system the way I like it.
• My windshirt is a strong red color, I think it’s good to have one brightly-colored garment if you need to flag attention in an emergency, and with my windshirt being that piece I can keep all the rest of my gear in the subdued colors I prefer.

I find them very useful on various levels.  For active insulation and for protection for my puffy and to boost it’s insulation a bit since most of mine are sewn through.

For active insulation, i most often wear it with a baselayer made out of polartec power dry high efficiency grid fleece fabric (Cap 4, etc) or fishnet. The combo with a good windjacket provides surprisingly enough insulation for hiking down to even down to low 30’s no problem, but also allows to vent/dump a lot of heat fast and efficiently if needed.

I don’t do much overnighters in the late spring or summer because i live in the SE, but do more day trips.  Can’t say that i’ve ever worn a windjacket during one of these unless it was for supplemental rain protection in combo with a modified poncho.

The general question about windshirts is why carry a windshirt when your rain jacket can also block the wind.

First you want to understand the concept of air permeability in your clothing, also known as breathability. When your clothing insulates while still having good air permeability, you overheat less and stay at a more comfortable temperature level at varying levels of activity. Also, air circulation is necessary for your sweat to evaporate.

A good windshirt blocks most of the wind while still retaining air permeability. A rain jacket has very little air permeability so you sweat buckets on the uphill, get chilled on the downhill, and your sweat can accumulate in your clothing.

You generally layer a windshirt as needed over breathable layers like fleece or wool to block wind or retain a little more heat. A windshirt works great over a base layer when you are just a little chilly, but not enough for a thicker jacket. Insulated jackets with tight nylon shells are wind resistant so there isn’t as much of a need. Even if you have an insulated jacket as your main layer, you can experience being too cold in a base later and too hot in the jacket, the windshirt fits in between that space.

The other value of a windshirt is that it can handle light rain. Instead of using a non-breathable rain jacket and accumulating sweat, you can stay a lot drier with the breathable windshirt that allows your sweat to evaporate efficiently. So you wear the windshirt in light rain and only put on the rain jacket when the rain gets heavier. This is why I consider a windshirt an essential clothing item for rainy weather in addition to a rain jacket.

Well, here in the Adirondacks, a wind-shirt doesn’t work that well, nowhere near rain resistant enough (I get rain 40-50% of my days out) and nowhere near warm enough to use in camp. I usually carry a standard,  cheap, rain jacket at ~6oz (nylon/PU.) They usually last about 5-6 years before the tape comes loose.

Another SE walker here.

I have to agree that windshirts are probably used most in places like mountains above the tree-line. There, a brisk wind can get cold really fast on otherwise pleasant days. So the shirt cuts the wind without adding much insulation.

Here in Louisiana a tightly woven shirt does the job just fine. Wind blocking isn’t as necessary but  in winter an extra light layer comes in handy. In summer and early fall/late spring I prefer to get wet when it rains because it feels good when you’re hiking in 70F. I do have an umbrella or poncho in case I need it though.

Is this thing intended to go over your insulation layer (the high loft Jacket?) If so, I’m going to have to find a bigger wind jacket.

I made the mistake once of climbing a peak and throwing on my down jacket with a rain shell over it, at the time the shell doubled as my windshirt. The vapor coming off my back was trapped by the shell and drenched the the feathers in minutes. The down jacket was pretty useless after that.

A better option would have been to use a windshirt under the jacket. The shirt would have stopped or slowed the vapor and protected the down.

I wear a windshirt (in my case a Montbell discontinued version of theirs, about 3 oz and packs quite small) often. In the morning, when I want to pack away the insulation (down jacket, or my Montbell Thermawrap) with all the other insulation I keep in the pack liner to keep it dry (because that is the function of the pack liner – fall in a creek, everything in it is dry. Sudden pack-soaking downpour, everything in the pack liner… you get the picture), and yet it is still 30-40F, the windshirt keeps me warm enough until we are moving. In very light rain, the windshirt is just enough, unless it’s continually raining or misting for more than an hour. In sudden chilly conditions – climbing up a pass, the breeze gets chilly, and the pass itself can be cold thanks to that upward air movement common to notches or narrow gaps in ridges – it makes a good easy-on, easy-off layer. I also have worn it over the day’s shirt and under the 200-300wt fleece shirt, when day temps are 20-30F and breezy, seriously pumping up the warm for my torso.

I do hike in the Sierra Nevada, and on western coastal ranges in winter – for example, going to Point Reyes over the New Year holiday – when temps are sub-freezing and that just-enough layer can get me through an early morning of onshore breezes until the sun is fully up and I want to go to short sleeves.

Ive used my wind shirt and my umbrella in all but heavily driving rainstorms. Didn’t have to use my rain jacket until the last parts of the PCT and heavy monsoon storms in Arizona/NewMexico and Colorado. I much prefer the wind shirt/umbrella combo, so much easier to manage core temps.

First of all, Montane runs at least a size small for US sizing.

Windshirts block wind and fend off light rain. It keeps the warm air in and the cold air out. They make a perfect “cap” to fleece and other mid-layers that are too porous to wear alone. It makes a 3-in-1 jacket that way

If you get a light color, it can be good for sun protection and for bugs too.

If you replace your Montane, look for a more breathable model.

In practice, you might wear it over your base layer starting out  on a cool morning or when there  is cold wind or light sporadic rain. You might add if when topping out some switchbacks and have a cold exposed traverse, or going downhill on the shady side— those times when it is cooler and your activity level has dropped. It helps to think of it as a shirt rather than a jacket.

Fantastic for biking and boating too