Which capilene weight?

Prolite Gear did some testing of these and found that Capilene 3 wicks quite poorly.

Honestly, considering those conditions and that you run cool, but still sweat a lot, Capilene 4 will be your best bet because it has the least amount of skin to fabric contact, with more void/air space. So, no matter how soaked it becomes, it will still provide some noticeable insulation (via the void/air space) provided you have a windjacket or rain jacket over same.

The stuff is quite good. While it's fairly warm with a good wind/rain-jacket/ all closed up, opening up the windjacket and zipping down the neck of the Cap 4 makes it noticeably cooler and you can dump a lot of heat and moisture.

There is probably not a better baselayer or midlayer out there than Polartec Power Dry High Efficiency high void grid fleece fabric (which Cap 4 is made out of). I recommend the Hoody version.

Brynje polypropylene fishnet is also really good for those conditions. The newest versions have antimicrobial treatment, but not having tried the new versions don't know how well it works. Hard to get the new stuff in the US though.

I hike in the SE and wet/damp and in the 30's is pretty common during winter, i use the above two the most as a baselayer or midlayer. Nothing better ime/o. I've used from the temps/conditions you specified down to single digits (but i will throw in a midlayer or two depending).

Video of Prolite Gear talking about the testing of Capilene 3

Capilene2 is better, unless it's very cold(for me, anyway, as I run hot).
Capilene2 does everything well, I think, though some have commented that it gets funky very quickly. My experience has been that it does get a slight odor in just a day, but I have to intentionally sniff it. I've only begun using it fairly recently, but have had the opportunity to wear it for 3 days straight twice, and once for 5 days. It wasn't unpleasant, and performance-wise it's probably the best lightweight baselayer I've used. Comfortable, decent warmth when layered, highly breathable, dries very quickly, all that good stuff.
Capilene3 is cozier, but doesn't breathe as well, or dry as quickly, as it's thicker and more densely woven. I've only hiked in it when temps were low(teens), but like it for wearing in camp and sleeping.

Cap 4 would work well at those temperatures.

If you are looking to just use on layer, I think the Cap 4 hoody would be the best bet for those conditions. I like a layering system though, and for these conditions, and cooler, I always go with a Cap 2 long sleeve crew shirt, then the Cap 4 hoody over it. Great combination for those temps. When hiking uphill I can unzip the front zip on the Cap 4, and when going downhill, or stopping for a break, I can zip the Cap 4 back up and even pull the hood over my head if needed. Add a wind jacket to this, and it's even more versatile.

"I like a layering system though, and for these conditions, and cooler, I always go with a Cap 2 long sleeve crew shirt, then the Cap 4 hoody over it."

Both from experience and theory, Cap 4 shines most when worn next to skin. It's a bit like a fishnet concept, except that Cap 4 also wicks too. The idea is to have void, stilled air space next to skin because something that has much more fabric/fibers touching the skin will conduct heat away much more efficiently when it gets wet with sweat or otherwise.

The stilled air space will continue to insulate much better as you sweat than wet fabric. Air has a super low thermal conductivity of .02 (k-W/(m K)), and most fabrics range between .14 (the least conductive) to around .3 or so, but while dry the air space between and around the fibers provides most of the insulation, but as soon as they get wet that goes out the window and then the only barrier between you and the cold is the level of thermal conductivity of the material itself, which is much higher than air.

A slightly loose Cap 2 ls over the Cap 4 would be more efficient for warmth retention and overall comfort during cool to cold wet conditions.

I had wondered about the Capilene 4, but the description "expedition weight" threw me. My winter excursions are hardly expeditions, believe me. Now, to find a sale!

Yeah, it is a little confusing. It is their warmest baselayer, but being so breathable on it's own, it has a wide comfort range when using or tweaking in combo with a good wind/rain jacket. In the high 40's, if it's not raining or not that windy and if i'm working hard, i would likely be tempted to take off the windjacket until i stop.

Alone and/or in combo with a windjacket, i can use this as a system from about about 20* F to 25* depending on terrain, to around 50*F but again in the latter, i'll likely unzipp or take off the windjacket unless it's full on raining or moderately windy.

That's a pretty hard to beat comfort range for just a baselayer and windjacket. Course other people's comfort ranges will be different–i run warmer above average, as a tendency, during both rest and active.

I think Dave Chenault calls this fabric (PPDHE) and the Cap 4 hoody his most favorite advancement in clothing evolution so far, or something like that.

"Both from experience and theory, Cap 4 shines most when worn next to skin. It's a bit like a fishnet concept, except that Cap 4 also wicks too. The idea is to have void, stilled air space next to skin because something that has much more fabric/fibers touching the skin will conduct heat away much more efficiently when it gets wet with sweat or otherwise."

"A slightly loose Cap 2 ls over the Cap 4 would be more efficient for warmth retention and overall comfort during cool to cold wet conditions."

My experience has been the opposite…. with the cap 2 layered under the Cap 4, I am a quite bit warmer than when wearing the Cap 4 next to skin. The Cap 2 fits pretty close, as does the Cap 4, so trapped air is still there. As well, the Cap 2 is a very loose knit material, so it doesn't really hold much sweat for very long, and it does a great job at passing it into the Cap 4.

Before I got the Cap 4 two years ago, I was wearing the Cap 2 long sleeve crew shirt under an R1 for a few years and it was the same. The difference for me is that the R1 is a bit warmer than the Cap 4. Now I don't use the Cap 2 & R1 combo unless I am planning to hike in temps less than 20 for most of the time. For temps over 20, the Cap 2 with the Cap 4 hoody layered over it has worked extremely well for me here in the wet southeast conditions. Highly recommend it!

Something else that had put me off the Cap 4 were the complaints about fit. In particular, reviews complaining about the length and the shirt not staying tucked in. They were mostly centered around 2013. 2014 any better?

Mine is a 2012 version, so I cannot comment on the previous years fit. Although, it does seem like fit is a thing of wonder from year to year on many Patagonia garments. The best thing I could recommend is to find somewhere that you can try one on in person before buying, or to order online from ac company that is happy to do returns.

"My experience has been the opposite…. with the cap 2 layered under the Cap 4, I am a quite bit warmer than when wearing the Cap 4 next to skin. The Cap 2 fits pretty close, as does the Cap 4, so trapped air is still there."

If you are sweating heavily, the air space between you and the Cap 2 and in the Cap 2 will be taken up by water and then it will become much cooler on the skin.

With Cap 4 directly on skin, no matter how heavily you sweat with it having so much void space, there will still be plenty of stilled air space, thus providing more warmth and comfort when you are sweating heavily. To get this to maximum effect, it's best to wear a slightly loose Cap 4 hoody.

This is basic physics, and why thicker fishnet is fairly popular in the Scandinavian countries and the go to baselayer of the Norwegian army. It's a similar principle used with a different fabric. I also have used Polypropylene fishnet as a baselayer, and with a thin, very well wicking layer right on top of the PP, it works just about as well as the Cap 4 but builds up stink faster.

Ultimately though, in most regular and non extreme conditions, it appears to be more a comfort thing overall. Richard Nisley tested the effects of different baselayers (including fishnet) on body core temps during and after exertion levels similar to bacpacking and found that core body temps were the same for different baselayers/fabrics. However, he noted that perceived comfort level was different. This indicates to me that the body is fairly adaptable.

I don't know what the conditions of the testing were though. If you add more extreme conditions like cold rain, extreme cold, etc it may possibly become more important.

Anyways, the reason why Polartec designed Polartec Power Dry High Efficiency high void grid fleece baselayer fabric the way they did, was for the reasons and physics i have hopefully clearly outlined. Subjective experience can be affected by many, many variables.

"If you are sweating heavily, the air space between you and the Cap 2 and in the Cap 2 will be taken up by water and then it will become much cooler on the skin."

Luckily, I am one of those folks that don't sweat very much, and especially in the winter, although, when hiking, I do try to keep myself on the cooler side by wearing as little as I need, which helps with not sweating so much. Don't get me wrong, I do sweat, but the Cap 2 and the Cap 4 combo does an excellent job at moving that sweat away, and keeping me feeling warm and dry.

I understand that all the science in it may go against the way that I use/layer it, but for me in the conditions I have used them in (wet and cold southeast conditions, and even in the PNW), it has worked better for me with the Cap 2 under the Cap 4.

Hi Chad,

That is the most efficient way to backpack in cool to cold conditions, sweat as little as possible. I usually try to do that as well, thought sometimes it's hard.

Take care fellow South Easterner

If you are sweating heavily in the 30s-40s, you are wearing the wrong clothes.

"If you are sweating heavily in the 30s-40s, you are wearing the wrong clothes."

Possibly, but i find it depends on various factors especially exertion levels. I also find that pretty much no matter what i wear or how cold it is, my back sweats heavily because of wearing a pack.

I must find me one of these magical packs that gives you a foot of convective air space between you and your back.

Yeah, the only time sweat is really an issue for me is during the middle of our summers, then it doesn't matter… when temps are in the 90's, or worse, nearing triple digits in the middle of the day, sweating is part of it! In the 30's and 40's though, sure a little, but not heavily for sure! Gotta manage those layers. And Justin, I love my Arc Blast for that reason! :)

I just ordered the SMD Fusion, so i'm hoping it will help a bit in that regard. Most packs i've used have been more back huggers.

I like MEC T2 over Capilene 4. It's thinner, so not as warm, but it's made from the same material, so all the same benefits. Cheaper, too, once you have a MEC membership. I own MEC T2 and Capilene 2. Capilene 2 is also an excellent layer for warmer temperatures.

All this time, i was mixing up T3 and T2 MEC models dagnabbit. Awhile back i bought a MEC hoody made out of PPDHE grid fleece used from BPL gear swap, forgot which model it was and have been calling it the T3.

After i added my own Polygiene like treatment* to it, i consider it a great piece.

* I made some silver chloride in water suspension from an electrolysis process, took the T2 and removed some dye from same, then went through a boil/redye process with the silver chloride in water suspension in same. Apparently, as the dye bonds to the substrate of the polyester fiber, it bonds the silver chloride particles with same to the fiber.

It now has some anti odor properties, though possibly (likely?) not as good or durable as the real deal (Polygiene)?

From my experience, Cap 4 is a bit too warm for temps above freezing while backpacking. Especially if I'm working hard gaining elevation. Cap 2 would work well while moving and supplemented with a light shell and mid layer (even if it's just another light Cap 2-ish weight shirt)if needed. Add a heavy fleece or puffy at rest (e.g. snack/water breaks, camp, photo ops).