Yes, it can get really cold and really wet. The Cordillera Real range is close to the Amazon lowlands, so a lot of moisture comes up from there. May is the bridge month from the wet months to the dry, so you could have great weather, or see lots of snow.
And its high elevation, so it can get cold. Im inclined to suggest a mid-weight down parka with a hood, not a more stripped-down one. Marmot makes a nice one called the Mountain Down Jacket ($275; marmot.com), which has a shell of Marmots proprietary waterproof MemBrain material, plus decent 650-fill down. It has a zip-off hood and lots of pockets, and it weighs one pound, eleven ounces. I think it has a good feature-set for the trip youre planning. Unfortunately, its a little hard to find right now, unless youre a size small or extra-large.
I also like Mountain Hardwears Sub Zero SL Parka ($295; mountainhardwear.com). Its a little heavier piece than the Mountain Down Jacketat two pounds, five ounceswith a bit more 650-down insulation and a beefier shell. It also uses a proprietary waterproof shell, Mountain Hardwears Conduit material. It has a detachable hood, too. Nice jacket. Try backcountry.com for a good selection of sizes.
Budget got some room? If so, then take a look at the Feathered Friends Frontpoint Parka (featheredfriends.com). It uses really high-grade 850-fill down in a traditional parka cut (a little long) with a detachable hood. It comes in at just under two pounds. Get it with either an Epic Nextec shell ($395) or eVent ($429). I recommend the eVent; its a great waterproof-breathable material.
Looks like an awesome range. Send us some photos when you get back.
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