What Does BKN Mean in a METAR?
BKN means broken clouds: 5 to 7 oktas; the lowest broken layer is a ceiling. It stands for BroKeN.
BKN in a real report
BKN015
What it changes for you
BKN is the lowest coverage that counts as a ceiling, and that single fact
drives the flight category.
BKN015 means broken cloud at 1,500 feet, and that is a 1,500 foot ceiling. The
same height reported as SCT015 is not a ceiling at all, because more than half
the sky is still open.
Reading a stack of layers
Layers are reported lowest first, and coverage is cumulative. So FEW010 SCT020 BKN040 describes the sky building with height, and the ceiling is 4,000
feet.
A CB or TCU suffix on a broken layer, as in BKN025CB, adds a thunderstorm
or a building cell to the picture and matters more than the height does.
Related codes
Decode a report containing this code
Paste a METAR, TAF, PIREP or SIGMET into the WxDecoder decoder. Every group comes back in plain English. The raw code sits beside it, so you can check the decode rather than trust it.
Frequently asked questions
What does BKN mean in a METAR?
Broken cloud, covering 5 to 7 eighths of the sky. A broken layer counts as a ceiling, so the lowest BKN layer sets the ceiling for the flight category unless something lower is overcast or an obscuration.
Is BKN considered IFR?
It depends on the height. A broken layer is a ceiling, so BKN005 gives a 500 foot ceiling, which is IFR. BKN050 gives 5,000 feet, which is VFR. The coverage sets whether it is a ceiling; the height sets the category.