Insulating layers?

[aguerra.1993]

Hello again, I appreciate all the information I get from this website. In two months I will be traveling to Colombia and will be doing a ton of hiking in the Andes at fairly high elevation. I might even try to submit an article with photographs for the magazine, but anyways back on topic. I am traveling light, only taking my hiking pack that is 65 liters (+10 but I never extend it, never needed to). I'm in the market for an insulating piece as I may be doing some mountaineering there on peaks around 5,200m or so. I am looking at the Arcteryx Atom LT and the Patagonia Nano Air, they both fit nicely but I am unsure on if it's supposed to be a slim fit or not because I've never owned a piece like this. If I am layering with a lightweight/midweight fleece baselayer, a lightweight fleece, and then this synthetic jacket, I should be plenty warm for active times with a hardshell over this. My main question is, would it be better to get two synthetic jackets, one light one around 60 g/m2 and the other somewhere around 80-100g/m2 or should I get fairly warm down jacket? I am not sure if just one 60 g/m2 jacket would be warm enough for hanging out at camp at night and in the mornings. Do you usually bring along a synthetic jacket and a down jacket? Do you do any hiking or climbing with the down one on? Thanks for any info!

[Aaron Zagrodnick]

Hey @aguerra.1993, sounds like you have an amazing trip planned! I'm a down jacket user, but I can say I'd probably go for just one jacket for the sake of simplicity, space, and weight...I only ever take one. In regards to fit, I just go with what's comfortable here with the anticipated layers...good coverage and unrestricted movement / comfortable without lots of wasted space. If you're in between, probably best to try both sizes.

I'm not a climber, and not sure what type of temperatures you're expecting, but in regards to hiking it would be rare to find me hiking in a down jacket but if I'm cold, I will. This is usually only when it's very cold, the sun isn't out / it's dark, and I'm headed downhill at an easier pace and am not generating much heat, or I found myself chilled for some other reason, and the jacket comes off at the first hint of overheating. But usually I keep the jacket in my pack and it's only used in camp. 

Hopefully this helps! Good luck with the decision and personally...I'd go with something that has a hood as well. 

[aguerra.1993]

On a lot of the hikes I think the temperature will be mild, probably not reaching colder than 40 degrees, but the higher elevations I am wanting to do are snow-capped all year round and there are glaciers, so it gets pretty cold up there. I wouldn't be up there for extended periods though. I think I am going to bring a synthetic to hike in if needed and a down one to wear over it for breaks, at night around camp, etc.

[Aaron Zagrodnick]

Whatever works is without a doubt always best. Sounds warm!

[toejam]

I never hike in a puffy jacket. I have a Sierra Designs Gnar down hoody for around camp on normal backpacking trips. I have a heavier down jacket for breaks & camp on colder trips. I've rented a heavy hooded down parka for breaks & camp on Mt. Rainier climbs because they are expensive and I never need one any other time.

But I hike & climb in thin layers - fleeces, soft shells, and even a light goretex jacket if an icy wind is blowing. Puffy jackets don't breathe  well enough for a lot of physical activity, and you don't want to get a puffy sweaty, whereas it doesn't hurt a fleece to get sweaty.