What specific atmospheric condition does the term 'ceiling' refer to in weather reports?

The term 'ceiling' in weather reports specifically refers to the lowest layer of clouds or the height at which visibility is significantly reduced to the point where potential flight operations may be affected. In aviation, the ceiling is a key metric as it determines the minimum altitude at which a pilot can safely operate an aircraft under Visual Flight Rules (VFR). This implies that if the cloud cover is low (meaning the ceiling is low), it might limit visibility and inhibit a pilot’s ability to sight-see and navigate safely.

Understanding that 'ceiling' concerns the lowest layer helps pilots interpret weather conditions effectively for safe flight operations. High cloud formations, areas of high pressure, or temperature inversion layers pertain to different meteorological aspects and do not capture the specific reference intended by the term 'ceiling' in the context of aviation weather reporting.