How to Pack for High-Altitude Hiking in the Andes

Prioritize a strict layering system to manage extreme temperature swings and moisture. Pack for conditions ranging from freezing nights to intense UV exposure at altitudes above 4,000 meters.

  1. Build your base layer. Bring two sets of moisture-wicking synthetic or merino wool base layers. Avoid cotton at all costs; if it gets wet from sweat or rain, it will make you cold and potentially hypothermic at high elevations.
  2. Master the mid-layer. Carry a lightweight fleece or grid-fleece for active hiking and a heavier down or synthetic puffer jacket for when you stop moving. Even in summer, Andean temperatures drop below freezing as soon as the sun disappears.
  3. Prepare for extreme UV. The atmosphere is thinner in the Andes. Pack a wide-brimmed hat, polarized sunglasses with a category 3 or 4 rating, and at least 60ml of SPF 50+ sunscreen. You will burn in 15 minutes without protection.
  4. Select your footwear. Use broken-in, waterproof hiking boots with ankle support. Bring three pairs of wool hiking socks—one for the trail, one for camp, and one spare—to prevent blisters and keep feet dry.
Do I really need specialized gear?
Yes. Weather in the Andes is unpredictable. A sudden hail storm or high winds at 4,500m can be dangerous if you only have light clothing.
How do I deal with altitude sickness in my packing?
Pack a pulse oximeter to monitor your blood oxygen levels and consult your doctor about bringing Acetazolamide (Diamox) for the trip.