In what units is the amount of sky cover for each layer observed?

The amount of sky cover for each layer is observed in eighths, which is a measurement that allows meteorologists to quantify how much of the sky is obscured by clouds. The sky is divided into an octant system, with the total sky represented as a full circle of 8 divisions. Therefore, if an observer notes that half of the sky is covered by clouds, this would correspond to 4 eighths. This method provides a standardized way to describe cloud cover, making it easier to communicate weather conditions.

Using tenths, quadrants, or sectors would not provide the same degree of granularity or standardization that eighths do. Tenths could lead to confusion, as they break the sky cover into finer, non-standard slices which are not typically used in meteorological practice. Quadrants would divide the sky into four parts, which may not adequately represent the variations in cloud cover. Sectors are not a common measurement used for cloud cover, making eighths the preferred choice for clarity and consistency in weather observations.