Definition
The altitude value displayed on an aircraft's altimeter when the instrument is set to the current local altimeter setting. In a surface weather observation context, it refers to the altitude indicated by an altimeter at a known field elevation, used to verify the accuracy of the reported altimeter setting.
Plain English
The number you see on the altimeter dial. It tells you what altitude the instrument thinks you are at, based on the pressure setting it has been given.
Context Anchor
Seen in surface weather observations and heard in airport weather broadcasts before taxi, takeoff, approach, and landing.
Derivation
Altimeter comes from Latin altus, meaning high, and meter, meaning measurer. Reading means a value shown or reported by an instrument. Together, the term points to the reported value used by the height-measuring instrument.
Why Pilots Care
An incorrect altimeter reading can lead to terrain conflicts or airspace violations if the pilot does not apply the proper altimeter setting.
Grounding Statement
The altimeter reading is the local pressure reference that tells the altimeter what “correct” means for that place and time.
Intuition Check
Do not read this as the altitude currently shown on the altimeter. In this weather-report context, it means the pressure value used to set the altimeter.
Example Sentence 1
With the local altimeter setting dialed in, the altimeter reading on the ramp matched the published field elevation within 20 feet.
Example Sentence 2
During the approach the altimeter reading showed 1,200 feet when the aircraft was actually lower due to an outdated pressure setting.