New to UL, what insulating layer should I purchase?

For the lightest insulation layer upper wise will be a down sweater theras a handfull of options under 10 ounce I use a montbell down ul inner parka there's others as well and I would go for one of those dry ducks emergency poncho they should be tougher then a plastic one fwiw

Down wins, IMO. Depending on the range of temperatures you expect to encounter, it could be as simple as a Montbell Ex Light.

I /REALLY/ don't like wool as an insulating layer. It's too heavy for its warmth and takes too long to dry. Fantastic as a baselayer though. Fleece is by no means UL, but has its place and is cheap.

I like the dependability of a rain jacket. Plenty of folks on here prefer lighter options (like a poncho).

I just picked up a synthetic bpl cocoon hoody.

10oz in a size large which is pretty much the same for a down parka.

I also dont have to worry about getting it wet in all of the rain in the PNW.

For the Southern Sierras I would think that down would be the obvious choice. The "gold standard" that everything is compared to is the Mont-Bell UL Down Inner Jacket. There have been a lot of new entrants into that market lately, some perhaps slightly better, but it is still the garment to which all others are compared.

Don't let the knee-jerk reaction of the fanatics sell you on down just yet. I think it is far more important to understand the merits and drawbacks of down vs synthetic and then make your own informed choice.

For the record I'm a down fanatic, too, but I try not to proselytize.

So, in general:

DOWN
Expensive.
Lighter for the warmth.
Compacts smaller.
Will last decades if properly cared for.
Worse than useless when wet.
Difficult to dry.

SYNTHETIC
Cheap.
A little heavier for a given warmth.
Bulkier when compacted than down.
Given routine use has at best a 5-year lifespan with full performance.
Also pretty useless when wet, but certainly better than down.
Much easier to dry after getting wet than down.

Also, if you're buying worse than 700-fill down the advantages in weight/bulk get pretty minimal compared to synthetics. If you do decide upon down I'd strongly recommend committing to 800-fill or better.

Forgive me if I have told you nothing you don't already know.

As a (for the moment) Coloradoan, I like down. I understand that most people in the PNW prefer synthetic, for the obvious practical reason. You will NEVER spend a night as miserable as one in a truly wet down bag. But you already have a sleep system, and you're asking about insulation layers. Personally, I don't prefer down over synthetics nearly as much for clothing as I do for my sleep system. It is easier to have a bad moment and end up with wet clothes than it is to find yourself with a soaked sleep system. Also, synthetic doesn't come pouring out of a minor rip in the outer shell the way fine down can.

Pick yer poison. But especially if you're on a budget synthetics aren't NEARLY as horrible as the fanatics will tell you, especially for clothing as opposed to a sleep system.

I'll let people with more than zero experience in the Sierras advise you on how wet/dry conditions you can expect.

As far as rain gear- I think that if you can keep the weight of a WPB top below 12oz and the WPB pants below 10oz you're not doing badly, though you can certainly find much lighter if you try. I have GoLite Reed pants and a one of their discontinued tops for more severe weather. Somebody here is selling something similar in Gear Swap right now. A lot of people here detest GoLite because they seem to be moving more mainstream, but I think that their lighter clothes are still a decent compromise between weight and durability.

It depends on whether you are referring to the true S Sierra (Kern plateau) or the southern E Sierra. For the S Sierra, I take a LS shirt, merino sweater and rain shell. The rain shell doubles as insulation in the off chance it gets cold or wet.

Now, for any part of the E Sierra, I always take the full regalia: LJs, LS shirt, merino/fleece, down vest and rain shell. As anyone who has spent time up there knows, once you are above 11k, all bets are off. That is, you have to take the whole kit to be ready for any contingency. The high Sierra is the land where UL becomes a challenge.

+1 Dean. I use synthetic and have never even considered down. Mind you, I use my jacket as part of my sleep system and it handles condensation and body moisture as a first line of defense into my down sleeping quilt.

I was in a similar situation recently and went with the Montbell Thermawrap synthetic jacket. Still very light (10oz. for size large) and quite warm. I have a long sleeve merino wool shirt that I wear under it when around camp, and the combo keeps me comfortable down to the low 40's. I chose synthetic because I do live in the Pacific Northwest and wanted something that could handle small amounts of moisture. Keep in mind what you will be layering the jacket with. In my case, the long sleeve merino wool, Thermawrap jacket and a light weight rain shell (Marmot Essence) are all I need for typical three-season conditions. All that being said, down is warmer, and if you don't want to think about layering it's a better choice. At some point I expect to add a UL down vest to my collection for colder weather trips.

most important question … what are the lowest temps you are expecting in camp when not in your sleeping bag …

"For the S Sierra, I take a LS shirt, merino sweater and rain shell. The rain shell doubles as insulation in the off chance it gets cold or wet."

I think this is cutting things pretty close unless you are one of those rare birds who is impervious to the cold. I have spent a lot of time in what you refer to as the true S. Sierra, and I would never even think of going there without a true insulating layer, such as the benchmark Montbell UL Inner jacket, or even a WM Flight jacket. Much of the Kern Plateau is at or above 11,000', and it can get pretty darn cold there, even in July/August. A rain shell is flat out not an insulating layer.

"I was thinking about going with the BPL cocoon hoody, a light fleece or wool layer and a cheepy disposable poncho as my rain shell."

Jon,

This combination should be adequate for July-September, although the insulating layer is a bit on the light side, IME. If you do start to get cold, retreat to your sleeping bag, but for the most part you should do fine. You can use your poncho as makeshift windshirt, although it will not be as efficient as a true windshirt in trapping heat. Have you considered an O2 Rainshield or Dri Ducks shell as your WPB layer. Either wiould do, and also serve as a windshirt.

"such as the benchmark Montbell UL Inner jacket, or even a WM Flight jacket."

Any time that I go around there in July or August, I always have a thick synthetic shirt, a WM down vest, and a Montbell Down Inner Jacket.

Also, any kind of a real rain jacket will serve to trap all of that down-insulated body warmth around you. A poncho just kind of flaps around in the breeze.

A poncho is fine in a hot humid climate, or if you are going to be moving 100% of the time. When I think of the Kern Plateau, I don't think of hot or humid.

–B.G.–

"You will NEVER spend a night as miserable as one in a truly wet down bag."

Hmmmm. I've spent a few nights with a warm, dry bed but a truly angry wife that were pretty miserable……

Yeah,

Well I imagine what it's like to spend a night with your wife in a tent when she is wet and miserable:)

I was being imprecise. I should have said south of Siberian/Cirque. By the time you get to Tunnel, Kern Cyn or S fork, you're down to 8k. If you go north over the crest via Cottonwood /New Army, then yes, I take everything.

Thanks for all the suggestions and advice guys! Hobbes, the area I'm refering to is the Golden Trout Wilderness near the forks of the kern, little kern etc. This is the area that I'd be hiking at mostly.

Based upon the suggestions would the following be adequate for the location previously mentioned?:
1. Montbell UL
2. Beartooth Merino Wool Hoody
3. Marmot Precip
*LJ's?