What socks do you use?

Give very serious consideration to RBH Designs Vapr therm socks. They are custom made vapor barrier socks that I have found to be perfect. You will keep your toes because the socks are warm but also because you don't need to layer to the point of losing circulation potentially. I wish I had known about them before any of the times I have been frost nipped/ bitten.

Check out their website. I don't know how you could go wrong.

Best of luck,

Logan

^ +1 on the RBH VaprThrm sock. It's all I use in the winter whether I'm hiking or ski mountaineering. I went with the Hi-Rise version which has a slightly trimmer profile to fit in my AT ski boots. Ryan and Nancy were great to work with, they custom made me the socks with a shorter height similar to the standard model.

I use my RBH VaprThrm socks when I want a vapor barrier layer, with wool socks as an outer layer.

*** edited to add: sorry, I looked at the title and not the whole question. Below is my response for conditions above -5C. For cold conditions, I'm using Smartwool or a polypro/polyester blend, each of them thick and cushy.

Without getting into the question of whether the "Ray Way" is a religion and/or one that holds water, I did pick up several tips from reading Ray Jardine's book. One of which was:

Buy a 3-pack of cheap, nylon socks at Walmart, etc and use them on the trail.

I gave it a try. They give me enough rub-protection from the inside of my shoes, wash&dry really quick, weigh very little and last a long time.

Like many UL techniques, I also use it on business and vacation trips because I like to travel light. I have 6 pairs in tan for my hiking and to match many tan khakis. Now, I've picked up some black pairs to match my black loafers and charcoal-colored wool slacks.

Back when I was using cushy socks, SmartWool worked well for me. Wool needs to be washed far less often than cotton or synthetics.

Socks are super important and liners are as well. A VB sock will keep liners dry from the inside but a closed cell liner is key to staying dry from the outside. When you get soaked from snow, streams running across glaciers, little potholes full of water hidden beneath thin ice and a dusting of snow, river crossings, whatever, you can dump your liners out and dry them overnight. When I worked for NOLS we had to leave some open cell liners out in the sun for days and days before they dried. good luck on your trip.

Devin,

For probably the umpteenth time here on BPL I'll post my best solution. Might sound a bit strange but it works far better than any other VBL or combination of socks.

I use thin neoprene diver's socks that I've seam sealed with Seam Grip (for urethane coated tents).

Neoprene is a closed cell foam that is VERY warm for its thickness. Plus it wears very well and can be easily repaired with Shoo Goo.

P.S. MODE D' EMPLOY:
Wear thin polyester or polypro liner socks beneath the diver's socks and each night remove the diver's socks & turn them inside out to dry inside your sleeping bag. Also I put on a clean pair of the thin liner socks before turning in for bed. (Keep the skanky used liner socks in a ZipLoc FREEZER bag to contain the stench.)

Happy Trails

Or use merino liners.

if dbl's, with a modern closed cell foam liner you don't really need a vbl. you also do't need a thick sock/socks for insulation unless you are going to be in extreme cold. with either a thin or thick sock be sure the boots aren't to tight as to impare your circulation an leave you with cold feet. i've been wearing and sizing my dbl boots to fit with relativly thin smartwool ski racer socks. they have some extra padding along the shin and places where i might get hot spots and don't bunch up at all. i've also worn them with to-the-knee dress socks. i'm not sure what sock, or combination of socks i'd wear with a single boot in the conditions you described for a month unless i knew that most nights i'd have a place to dry out my boots. whatever direction you go in, be sure you play around with it some before you head off for a month. also, if your going with a group and there are guides or someone who's made the trip before ask them what they recommend. who better to know what you need.

good luck –

It also depends on the boots of course (if intended for winter mountaineering/higher altitudes they will have more insulation). My boots have 400 Priimaloft and for temps 0˚~ -20˚C I wear SmartWool Mountaineering Extra Heavy Crew socks. As much for warmth as for the nice padding they provide and to get the fit right. I wear thin Montbell liner socks underneath. Fits like a, glove if you will. Never had any blisters or hot spots with this combination.

I respectfully disagree with Richard when he says you don't need VBLs "with modern closed-cell (boot) liners".

IF the boot liners are truly closed cell OK, you can "get by" without VBLs. But most of these have sewn thru seams and some kind of inner footbed that may be removable – or not.
To me this means you do need a VBL, but just not as much as with, say, feltpacks.

My Scarpa 3 liners can get wet and I use neoprene VBLs. So "It all depends."