What does the acronym BKN signify in a METAR report?

In a METAR report, the acronym BKN stands for "Broken clouds." This term is a standardized meteorological abbreviation that indicates that the sky is covered by clouds in a significant way, with cloud coverage between 5/8 and 7/8 of the sky. This level of cloudiness means that there are substantial gaps or breaks in the cloud cover, allowing for some visibility of the sky.

Recognizing cloud coverage is crucial for aviation and weather reporting, as it affects flight operations, visibility conditions, and weather patterns. The distinction between broken clouds and other types of cloud cover, such as few clouds or overcast, is vital for pilots and meteorologists to accurately interpret weather conditions. In this context, "broken" signifies a substantial but not total cloud cover, differentiating it from "few clouds," which indicates less coverage, or "overcast," which means that the sky is entirely covered with clouds.