Definition
A small gas-filled balloon released from the ground and timed as it rises to determine the height of a cloud base. The balloon ascends at a known, calibrated rate, and the time taken for it to disappear into the cloud is used to calculate the ceiling height.
Plain English
A small balloon let go from the ground that floats up at a steady, known speed. Someone times how long it takes to vanish into the clouds, and that time tells them how high the cloud base is.
Context Anchor
Seen in weather observation and older surface weather reporting methods, especially when estimating cloud height from the ground.
Derivation
‘Ceiling’ here refers to the height of the cloud base above the ground — the ‘ceiling’ of usable visual airspace. The balloon is the tool used to measure that height, hence ‘ceiling balloon.’
Why Pilots Care
Provides the measured cloud base height needed to decide whether conditions allow VFR flight or require IFR procedures.
Analogy
It is like using a floating marker to find the bottom of a low cloud layer: if you know how fast the marker rises, the time it takes to vanish tells you about how high the cloud base is.
Grounding Statement
An observer releases the balloon, watches it climb, starts timing, and stops when the balloon disappears into the clouds.
Intuition Check
Ceiling does not mean the ceiling of a room here. It means the reported height of the lowest cloud layer that limits a pilot’s upward view.
Example Sentence 1
The weather observer released a ceiling balloon and timed its ascent to report a 1,200-foot ceiling.
Example Sentence 2
When the ceiling balloon disappeared at forty-five seconds, the station recorded a ceiling of eight hundred feet.