Trip Layering Planner
You live at 30 °C. Most places worth trekking are not. Tell us when, where and what — we’ll tell you what goes in the bag.
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Temperatures shown are typical seasonal ranges, not a forecast. Mountain weather moves fast and altitude costs you roughly 6 °C per 1,000 m of ascent. Check a real forecast in the week before you travel, and pack for the coldest night, not the average day.
Why merino weight is quoted in gsm. It is grams per square metre of fabric — the single most useful number on a base layer. 150 is a hot-weather t-shirt weight; 200 is the all-rounder most people should own; 260 is genuine cold-weather kit; 320 is for standing still in winter.
Down or synthetic? Down is warmer for its weight and packs smaller, but stops insulating when it gets wet. Synthetic — Montbell EXCELOFT®, Kolon Sport PrimaLoft® — keeps working damp and dries faster. Cold and dry, take down; wet or high-output, take synthetic.