Ceiling (cloud)


In aviation, ceiling is a measurement of the height of the base of the lowest clouds that cover more than half of the sky relative to the ground. Ceiling is not specifically reported as part of the METAR used for flight planning by pilots worldwide, but can be deduced from the lowest height with broken or overcast reported. A ceiling listed as "unlimited" means either that the sky is mostly free of cloud cover, or that the cloud is high enough not to impede Visual Flight Rules operation.

Definitions

; ICAO : The height above the ground or water of the base of the lowest layer of cloud below 6000 meters covering more than half the sky.
; United Kingdom : The vertical distance from the elevation of an aerodrome to the lowest part of any cloud visible from the aerodrome which is sufficient to obscure more than half of the sky.
; United States : The height above the Earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as broken, overcast, or obscuration, and not classified as thin or partial.