Definition
A ground-based system of automated sensors at or near an airport that continuously measures local weather conditions — typically wind, visibility, ceiling, temperature, dew point, and altimeter setting — and broadcasts the current observation by radio and/or telephone without human involvement.
Plain English
A set of automatic weather instruments at an airport that takes constant readings and reads the latest weather out loud over a radio frequency or phone line, so pilots can hear the local conditions any time.
Context Anchor
Pilots commonly listen to AWOS before takeoff, before landing, and while planning a flight to understand the current weather at an airport.
Derivation
The name describes the function: the system observes the weather automatically and reports it. 'Observing' covers the sensing side (taking the measurements); 'reporting' covers the broadcasting side (announcing them to pilots).
Why Pilots Care
Pilots use AWOS reports to decide if conditions are safe for takeoff, landing, or continuing a flight, especially at airports without a control tower.
Intuition Check
AWOS is not a forecast and not a person giving advice. It is an automated report of the weather being measured at or near that airport.
Example Sentence 1
Ten miles out, she tuned in the AWOS and noted the wind favored Runway 27 with a 1,500-foot ceiling.
Example Sentence 2
The AWOS reported a 10-knot crosswind and 3 miles visibility, so the flight was delayed until conditions improved.