I'm planning to hike the JMT beginning July 8th of this year, and have been working hard to lighten my load without breaking the bank. One option is to lose my heavy down jacket and fleece and replace it with a warm lightweight insulating jacket.

I'm planning on wearing the jacket with a baselayer (Patgonia cap 3) and a lightweight insulating layer (icebreaker or something equivalent), but at night around camp the new jacket will be my primary warmth. I'll also have a driducks raincoat for wind and rain at camp.

I'm trying to decide between the Montbell Alpine Light Parka, the Alpine down jacket, and anything else. I read Richard Nisely's posts on the CLO values of various Montbell items, but it's hard to factor that into the probable nighttime low temps.

Do you feel that the summer nighttime temps are warm enough on the JMT that the Alpine light parka would be enough, or should I go with the warmer Alpine down jacket? I'm willing to spend the extra $40 for the jacket, but don't want to spend over $180. It's my experience that it's nice to have warm enough clothing that you can sit outside without a fire and don't have to crawl into your bag.

Are there other options that are less than $180 that would provide as much warmth? Thank you!

I use a Down Inner Parka and find it sufficient for summer in the Sierras. The hood makes a big difference. If you do get cold just drape your sleeping bag over you.

I have a ProParka for sale in the Gear Swap that might fit your needs, light, synthetic and almost waterproof - unfortunately I never ended up using it.
Cheers, R

I cannot comment on the temps/experiences out west because I am in Texas. But I know for sure that my use of the MontBell Down Inner Parka has yielded terrificly surprising results. It is almost like having a sleeping bag. Especially when matched with the pants. I also have the alpine light jacket itself. When I match all three of those together, it is a huge impact. Personally for your situation I think reviewing the MB Down Inner Parka would be the way to go at around 8 oz.

you might have already seen it, but if you like Richard's theoretical approach, check out this link. In the chart you can relate clo values to thermal comfort ratings (given certain METs).

It really depends on how much time you spend sitting around in the evening. I hiked the JMT in August and never wanted more warmth than a merino t-shirt, lightweight fleece pullover (7 oz), and shell jacket. I was solo and usually took a long afternoon break and then hiked until dusk, so I didn't sit around in the evening.

Consider the possibility of rain and whether you would need an insulation layer for sitting out a late afternoon thunderstorm. If your Icebreaker layer satisfies this requirement- then it seems the lightest down or puffy synthetic jacket would be enough. (Again, depending on how you spend the evening).

I do like the looks of the MB Alpine Down Parka though!
I brought my fleece instead of a long-sleeve Icebreaker because the weight is slightly less and the fleece is thicker.

For my early July Sierra trip I'm toying with bringing my 13 ounce puffy down jacket or 15 ounce puffy Primaloft jacket- but I'd bring a lighter one if I had it. My main reason is that I've been using a 4 ounce pillow and the jacket makes a way better pillow, plus I won't be solo so there may be more sitting-around time. Either puffy jacket is not much more than the pillow plus the fleece. My camps will all be above 11,000 feet and with the current snowpack I expect evening temps to be cool. The JMT is generally a couple thousand feet lower.

Because most days will be on snow at 12-14,000' I'm planning on a long-sleeve RailRiders hiking shirt for better sun protection, plus a 140 weight merino T so I can live with myself. That brings back the question of whether to bring the fleece or not- If I don't bring the fleece I'd bring the Primaloft jacket so that I have a synthetic insulation layer. If I do bring the fleece I'd bring the down jacket.

Edited by jimqpublic on 05/06/2010 11:44:49 MDT.

A UL friend of mine was on the JMT at Wallace Creek one cold summer morning, and it was +10 F. For warmth, he used one WM down vest (5 oz or something) plus one MontBell down inner jacket (7 oz or something) plus a rain shell on top. He is a pretty hot-blooded guy, but he said that he needed every speck of that to get going in the morning.

--B.G.--

My solution is to go from sleeping bag to hiking in about 5 minutes.

But like I said if it's a social or leisurely trip then it makes sense to have more sitting-around insulation.

There's always the Sexy Hotness sleeping bag from Alite.

Thanks for the great comments so far. I especially appreciate the JMT-specific knowledge. It makes me inclined to bring something at least as warm as the Alpine Light.

I do like the idea of being able to spend some time outside stargazing, rather than hiking 'til night and then jumping into my bag. I'll definitely look into the Sexy Hotness, though I'm not sure if the warmth/weight ratio is worth it. Perhaps someone should post a MYOG article about a custom version?

I checked out the Mountain Hardwear Phantom, but I'm slightly concerned about the 15 denier material: there are a lot of rough rocks to brush up against out there.

Any other suggestions? Are the RAB jackets worth looking into? Perhaps there are brands I haven't heard of?

Sexy Hotness was a joke. Too many zippers, too much weight to warmth ratio. Unless of course it's a "very" social trip.

I didn't read all of that. Sorry.
I used an Alpine Light for mid-June to early July a few years back. I wouldn't call it overkill, but I could have gotten by with less and probably never been cold. I would use the Down Inner or whatever they call it these days. That and a light baselayer would be all you need unless you really like to sit around camp and do nothing.

If breaking the bank is an issue, you might consider the Eddie Bauer First Ascent Down Sweater. Its on sale for $100 right now at Eddie Bauer. No hood. Mine weighs 12.5 ounces. It's not as light as some of the others you are looking at, but its certainly a lot cheaper. Will Reitveld did a positive review on it awhile ago and thought it compared favorably to the competition.

I have a MB Alpine Light Down Parka plus a MB Extremely Light down jacket. I will be on the JMT starting August 21st.

I am currently leaning taking the Alpine Line Parka. The hood will make a really big difference and I can use that as part of my sleep system (Go Lite Ultra 20 Quilt) if it is cold, or I can just use it as a pillow if it isn't that cold. However, it is almost 8 oz heavier. I might invest in a nice down hat or balaclava and combine that with the Extremely Light down jacket. However, the alpine light parka would provide a lot of extra insurance.

I would probably opt for the down inner parka at that time of year. A little earlier or by mid September I'd go with something heavier. FWIW I've done sections in mid to late summer up there with nothing heavier than an expedition weight capilene pullover (probably equivalent to capilene 4 or maybe R.5) and a shell and been comfortable. If you run into one of the chilly nights or mornings just drape the sleeping bag to make due.

I think the main decided factor is how much time you spend lounging around in camp in the mornings/evenings. I have the down inner jacket and the Alpine Light down jacket. The down inner jacket is fine in fairly cold temps if I'm moving around, but I'm one who likes to lounge around in the evenings, and for that I need the added warmth of the Alpine Light jacket.

I ended up going with the Alpine Down Jacket. It was on sale ($150!) for the same price as the Alpine Light Parka, only two ounces heavier, and according to Richard Nisely, significantly warmer.

The reality is that I probably will be sitting around camp in the early evenings, and since this will be my first long trip using a quilt, I can also sleep in it if I need to.

It's overkill I realize, but at least this way I can have one item that's dedicated to keeping me warm in camp, and everything else can be worn hiking, where I tend to need much less warmth.

Thanks for the advice!

You also say that you are bringing a cap 3 and an icebreaker. As I am assuming you are not planning to hike in these, it seems like you may have one more insulation layer than you need. Bring one or the other, use it as a sleep/camp shirt, and the occassional "I'm cold at the top of a pass shirt."

Ive camped up there at about 11,000 in August. I had a MH wicked tshirt, cap3 zipped long sleeve layer and MB UL Inner down jacket (not the latest "Ex" version.) and was fine in the evenings and early mornings. Don't know for sure what the temps got down to but the condensation in the tent froze and there was frost on our packs that we'd left outside. I've also camped at 10,000 in September, when it got chillier, and was still fine with addition of a fleece beanie.
I'm starting from reds to WP in later Jul. This time I'm adding a WM Flash vest cos I'll be out for longer, going higher, with less ease of exit in case of freak storms/cold.

Last year out there I used a Patagonia NanoPuff pullover with success. It went well below freezing on several nights and it kept me very comfortable. Underneath I wore a Patagonia Cap 1 long sleeve.