The Yosemite Decimal System

The Yosemite Decimal System (YDS) is a scale used to rate the difficulty of climbing and hiking trails, especially in the U.S. It combines a number and a letter: the number (1-5) indicates the overall difficulty, with 1 being easy walking and 5 being technical climbing. The decimal decimal points further refine the difficulty within class 5, ranging from 5.0 (easy technical climbs) to 5.15 (extremely challenging). Letters (a, b, c, d) subdivide these levels, representing increasing difficulty. This system helps climbers assess the skills and equipment needed for a route.