Western Mountaineering Lynx (-10) GWS good enough for Idaho in Oct?

[Snowy]

I've backpacked with my WM Lynx in the fall and winter many times. I've pushed it to its rating inside a tent. If you know what you're doing it's up to the task, ymmv.

 

[Kevin Dill]

Always lots of talk regarding a bag warm enough for (x) temps. Certainly the WM lineup is about as good as things get these days, and they are well regarded for their conservative temp ratings. I wouldn't hesitate for one minute to take a 0-F WM bag and use it on a 0-F night.

Best to keep in mind that 100% of sleeping bags do not achieve any mentionable loft on the bottom side when in use. Body weight compresses insulation wherever weight is borne. At least 30% of the cold weather comfort equation is comprised of a well-insulated mat under the bag. Matching the mat-to bag-to conditions is simple logic. In cold weather I favor an Exped DownMat 9LW with about 4" of down-filled thickness under my body and bag. I have never been cold and have spent more than a few bitter nights sleeping in frozen valleys under the aurora.

 

[DUSTER]

Was out backpacking over the weekend (10-17-20) in the Sawtooths - slept on snow at '8500 feet in my Weastern Mountaineering Alipinlite (which is rated at 20 degrees). Shelter was a Integral Designs Mega Sola (Single wall bivy/tent) and pad was a Thermarest Prolite Apex (R value 3.8) . I put my Arc'Teryx Cerium LT down jacket over my chest, and slept in a heavy baselayer and wool socks. I was just warm enough. This was for sure the bleeding edge of use for this bag in those conditions, but it worked. I would say for me a 5 or 10 degree WM bag would cover all of my needs in the Stanley area up through the end of October. Much later and I would suggest a 0 degree, or warmer bag for sleeping in a tent or unheated trailer. I would also assume that a higher R-value pad would give me another 5 degrees or so on my 20 degree rated WM bag (or any of my others).

 

[prm]

I sleep in the CO Rockies at ~11.5k each year in Oct. I have a 10deg REI Magma bag. I have to keep some layers on, but it’s not terrible. Only one night I had to wrap my bag with my Woobie. That was really cold, 0 deg, or less as I was in a dark bottom along a creek (that was frozen over by morning).