Ceiling

Ceiling is the height above the ground or station of the lowest cloud layer reported as broken or overcast, or the vertical visibility into an obscuring phenomenon. In a US aviation weather report, a layer coded BKN or OVC can establish a ceiling. A scattered layer does not establish one.

How it works

Cloud bases in a METAR are reported in hundreds of feet above the station. A group such as BKN008 means broken clouds with a base at 800 ft above the station. OVC015 means an overcast layer at 1,500 ft. If the sky is obscured, vertical visibility may be reported instead.

Ceiling is not the same as the height of the highest cloud layer or the top of a cloud deck. It is also not automatically the same as terrain clearance. The observation applies to the reporting station and observation time.

Example

A METAR contains SCT020 BKN035. The scattered layer at 2,000 ft does not establish the ceiling. The broken layer at 3,500 ft is the reported ceiling. If a later report changes the layer to OVC010, the ceiling becomes 1,000 ft.

Why it matters

Ceiling is used in weather reports, forecasts, flight categories, approach planning, and regulatory comparisons. A ceiling can vary across an airport and along a route. Pilots should use the current observation, forecast, and applicable weather rules rather than treating a single ceiling as universal.

Read the observation time and compare a METAR with the TAF. The NOAA Aviation Weather Center provides current aviation weather products.

Related terms and tools

• Dew point
• Visibility
• METAR