Sky Cover

Sky cover is a term that denotes the amount of the sky that is expected (or observed) to be covered by opaque clouds. There are two different ways to quantify the amount of sky cover.

Source: WeatherSTEM

The first is a percentage based reference of the average sky cover. Percentages are relatively easy to understand and used by the National Weather Service (NWS) and media.

However, the NWS also uses a different metric to describe the sky hidden by clouds or obscurations- the amount is expressed to the nearest eighths or oktas.