Definition
The actual atmospheric pressure measured at a specific location and time, used as the current altimeter setting for that area. It reflects the real pressure conditions at the station rather than the standard sea-level value of 29.92 inches of mercury.
Plain English
The real air pressure right now at a particular place. Pilots set this number into the altimeter so it reads the correct altitude for that area.
Context Anchor
Seen when setting or checking an altimeter before takeoff, during flight, and before landing, especially when pressure is different from standard.
Derivation
Local' comes from the Latin 'locus,' meaning place. Here it signals that the pressure value belongs to a specific location, not a standard or global figure.
Why Pilots Care
Correct local pressure settings keep altitude indications accurate, preventing terrain conflicts or airspace errors when pressure differs from standard.
Grounding Statement
As weather systems move over an airport, the air pressure there can rise or fall, so the altimeter must be matched to that local pressure.
Intuition Check
Do not read “local” as a rough guess for a broad region. Here it means the pressure value for the specific area or reporting station being used to set the altimeter.
Example Sentence 1
Before descending into the area, the pilot dialed the local pressure of 30.05 into the altimeter's Kollsman window.
Example Sentence 2
A change in local pressure between departure and destination requires an altimeter adjustment to maintain proper terrain clearance.