Slim guy mid layer question

[Collin]

So I am 5'6" and 130lbs wet. Usually sleep cold and am hiking the JMT July 8-22. I have a not bad sleep system and most of the parts of my hiking clothes but have a question about a mid layer/insulation layer.

I plan on hiking in my 150 at merino long sleeve, nylon pants, and merino socks. In camp I got a EMS 800 down jacket and some long underwear top/bottoms. Should I just add warmth hiking with the down jacket? I am debating just adding another 150 merino shirt because (my heat transfer class tells me) insulation values are additive. I've just never done it hiking. Anyone else double up should the weather call for it?

I'm used to hiking in areas with less swings in temperature and my default seems to end up overpacking for warmth. Just trying to not go overboard with like a whole 'nother fleece or something.

[Venchka]

Don't hike with a down jacket on. You'll sweat and get the down damp to wet. A light wind proof layer over merino works wonders. Or just hike faster. Hiking a cool is better than hiking hot and sweaty.

Wayne


Sent from somewhere around here.

[gbolt]

Why stack a mid layer. Why not go with a 200 merino Long Sleeve (or greater) to wear by itself, or stacked on the 150. Another option is to add a Patongia Cap 4 on top as an outer layer. You can also work in a Wind Shirt as an outerlayer on single or combination layers underneath. I agree with Venchka, Down and Sweat do not match. Sweat in the Merinao Layers or Cap 4 outer layer because they will work damp and yet dry out quick. Down Jackets do not.

[egilbe]

Fleece vest or jacket will give you some more hiking warmth and flixibility. Dont wear your down jacket hiking.

[rocketsocks]

Well ive never heard of a "heat transfer class" where do you take that at? But yes they are additive.

[Dogwood]

Add a tee into the mix. Perhaps a 150 wt merino tee. Does your 150 wt LS have a chest zip. You may find wearing what you have is too hot on occasions. Consider mosquito protection with a buttoned down LS shirt permethrin treated skeeters have a hard time biting through. Save the EMS 800 jacket for camp and longer colder stops.

"Heat transfer class tells me insulation values are additive." Correct.

Good luck in your engineering degree. I guess a Masters in Mechanical Engineering. Fellow NJIT, U of South Florida, Rutgers, Upsala College, Thomas Edison State College, and Brookdale Community College alumni here.

[rocketsocks]

Oh yeah, well when I get cold I put sumthin on, when I get hot I take sumthin off, and when I get wet from sweat I'm moving way to fast, s?ow down, use a bandana to dry off..."school a hard knocks" and my mommy.

[Dogwood]

Im Forest. Forest Gump.

[rocketsocks]

Im Forest. Forest Gump.

beautiful!

[Collin]

Well ive never heard of a "heat transfer class" where do you take that at? But yes they are additive.

Heh. Mechanical Engineering major. It's as boring as it sounds.

[Collin]

Thanks for the posts. Looks like it won't be bonkers to bring another layer. I may poke around at a light fleece in case I need to be warmer on the move.

Unfortunately it is a BS in ME. I had a BS in political science but gave that up after the economy went to pot. This will be the last big hike before some (hopeful) employment.

[MuddyWaters]

double post

[MuddyWaters]

Daytime will be hot.

This is what windshirts excel at. A few degrees extra warmth over a long top. Its all u need. Rainjacket works too.


Clothing heat transfer is different. A big part is evaporative cooling from your body. Its not simple conduction or convection.

Regardless, a long john top, down puffy, ss top, and rainjacket us all u need. A windshirt is good because it crams in your pocket, easier than rainjacket. If you use poncho, def bring windshirt.

[Coffee]

I'm 6'1" 160-165 pounds. For hiking in the Sierra, I wear a Smartwool microweight base layer coupled with a wind shirt if it is cold or windy. I have a Montbel UL Down parka but it is never used while moving, only for breaks and in camp. This system has worked well for me on the JMT in 2013 and a section of the Sierra on JMT/PCT in 2015. In general, you will be hiking with temperatures well above freezing except perhaps early in the morning. For temps 40 and above, I never feel cold with the system I described. If the temp is above 50, just the base layer is fine. I do get chilly with the base layer and wind shirt under freezing but the duration of sub freezing temps while hiking is *usually* not long. As a supplement I can wear my rain layer over the wind shirt while moving if it is really cold. The only time I've packed a mid layer was on my foothills trail thru hike last February. I found it very nice one morning that started in the high teens and never got above freezing. But I wouldn't carry that heavy fleece layer on the JMT. Good luck with your hike.

[jimandlisas]

Throw in a very light wind jacket to the mix and it would be perfect. The wind jacket can go over the base layer to add warmth or keep out a cold breeze. If you are going to carry a light rain jacket this can also be used for this. A light wind jacket is also useful over the down jacket to add warmth at night or to protect your jacket from flying embers if you are in an area that allows a small campfire.

[George]

Heh. Mechanical Engineering major. It's as boring as it sounds.

go ahead and give them the u value of your clothing system, really get the heads spinning

[Dogwood]

I'm telling you you will have very warm hrs where a LS shirt especially with no chest zip might be too hot to hike in by itself especially on strenuous ascents in full sun especially if you're rocking pants. I see you rarely to never wearing a EMS Feather or Icarus 800 down jacket while you're hiking. It will be relegated to long stops and in camp and possibly for brief early morning or after sunset hiking hrs if you hike during those times. If you get up early and hike late I find it best to have multiple layers with great versatility addressing all those situations. For me and my JMT hikes in mid June, July, Aug, Sept, and up to mid Oct I want to be constantly adjusting my apparel and accessories to address my core and extremity warmth and comfortability. Even in July I'd be toting a beanie. I'd likely ditch a rain jacket and go for a high quality DWRed wind jacket, a light wt tee, a LS med wt merino shirt w/ deep chest zip, and either shorts or convertibles. All those three torso pieces can be worn at once or individually when hiking and/or when in camp. When in camp get in your tent or sleeping bag in rather quick order making that your main insulation in camp.

[MuddyWaters]

go ahead and give them the u value of your clothing system, really get the heads spinning

Clothing is measured in clo


1 clo = 0.155 K·m²·W⁻¹ = 0.88 RThis is the amount of insulation that allows a person at rest to maintain thermal equilibrium in an environment at 21°C (70°F) in a normally ventilated room (0.1 m/s air movement). Above this temperature the person so dressed will sweat, whereas below this temperature the person will feel cold

[rocketsocks]

Heh. Mechanical Engineering major. It's as boring as it sounds.

ah, I thought REI was maybe giving it.

[1Greywolf]

The only way to help this guy is to let him do want he wants.!Only after he does it will be know wat works and want won't. All our advice are all a joke to him.
Wanting to wear down in Southern California is a person to stupid to help him self or thinks we are to dum to realize
He is pulling our leg.
I hope to meet him on the trail