What code should be used for a layer of clouds covering four-eighths of the sky at an estimated nine thousand feet?

The correct choice for a layer of clouds covering four-eighths of the sky at an estimated nine thousand feet is represented by the code BKN090.

In aviation weather reporting, the code used to describe cloud cover includes a three-letter abbreviation that indicates the type of cloud cover and the altitude in hundreds of feet.

• The first part of the code indicates the extent of the cloud cover:

• FEW is used for clouds covering one-eighth to two-eighths of the sky.

• SCT denotes scattered clouds covering three-eighths to four-eighths of the sky.

• BKN stands for broken clouds, indicating coverage of five-eighths to seven-eighths.

• OVC refers to overcast clouds, meaning full coverage of eight-eighths.

A layer of clouds that covers four-eighths of the sky falls within the definition for BKN, as it represents a greater density of clouds than scattered but does not reach full overcast. The altitude indicator “090” indicates that this layer is at nine thousand feet.

In summary, the appropriate code for a cloud layer that covers four-eighths of the sky at nine thousand feet is BKN090, as it accurately reflects the