Which METAR code represents sleet or ice pellets?

The METAR code that represents sleet or ice pellets is PL. In aviation weather reports, different codes are designated to describe various types of precipitation. The code PL is specifically used for ice pellets, which occur when raindrops freeze into small balls of ice before reaching the ground. This phenomenon often happens when a layer of warm air lies over a colder layer, causing precipitation to freeze during its descent.

In contrast, the other codes represent different types of weather phenomena. GR stands for hail, which consists of balls or irregular lumps of ice that form in thunderstorms. UP is used to indicate unknown precipitation, which does not specify the type but can include a range of precipitation types. GS denotes small hail or snow pellets, which are different from sleet as they are typically softer and form in different atmospheric conditions. The specific designation of PL for sleet is essential for accurate communication in meteorological contexts, allowing pilots and meteorologists to understand the conditions they are dealing with.