What this solves
Most Yading trekkers over-pack rain gear. A 25 g emergency poncho covers the worst case at 1 % the weight of a Gore-Tex Pro. But under-packing is also a real failure mode — a 4 °C sustained rain at 4,500 m can turn a poncho into a hypothermia risk inside an hour. The right answer is a function of month, altitude, and how many days you'll be above 4,000 m. This tool works it out.
Build your rain-gear profile
How to read the result
Recommendation is the lightest option that meets your wet-weather exposure + altitude-wind exposure profile.
Regret risk is the scenario where you chose wrong — either the day you get cold & wet for hours, or the day you carried 600 g of shell you never used.
Below ~4,500 m in October, most of your days are dry enough that the 25 g poncho is the rational call. At altitude above 4,500 m, wind chill + cold rain is the killer — the lightweight hardshell is the right balance.
Limitations
FAQ
A: Ponchos flap, tear, and trap cold rain against your base layer in wind. They are great as a one-shot emergency layer; they are bad as your primary rain shell.
A: For Yading conditions, no — a ¥600 Decathlon MT100 will keep you dry through 4 of 5 storms. The ¥3,000+ shells earn their weight on multi-day rain at sea level with full pack.
A: Re-treat every 20 wash cycles with Nikwax TX Direct. A shell that wets out is the same as no shell.
A: For Yading's short treks, no — boardwalks and packed trails dry fast. For full Kora with 8 h rain days, yes — pack 200 g of rain pants.