Definition
An unmanned, automated suite of weather sensors installed at or near an airport that continuously measures local weather conditions and broadcasts them to pilots by radio and, at many sites, by telephone. Typical AWOS reports include altimeter setting, wind direction and speed, temperature, dew point, visibility, cloud height, and precipitation, with the specific elements depending on the AWOS level (AWOS-A, AWOS-1, AWOS-2, AWOS-3, and variants).
Plain English
A set of weather instruments at an airport that takes readings on its own and reads them out over the radio so pilots can hear current conditions before landing or taking off.
Context Anchor
Pilots commonly use AWOS during preflight planning, before takeoff, while approaching an airport, and before landing at airports that may not have a control tower or a human weather observer on duty.
Derivation
"Automated" because no human observer is required, and "observing" because the system's job is to observe and report weather conditions. The name describes exactly what it does: a weather station that watches and reports on its own.
Why Pilots Care
Supplies real-time weather observations at airports that lack human weather observers, supporting safe go/no-go decisions and approach planning.
Intuition Check
Do not treat AWOS as a forecast. It reports current measured conditions at or near the airport; it does not predict what the weather will do later.
Example Sentence 1
Ten miles out, the pilot tuned the AWOS frequency and copied the wind, altimeter setting, and ceiling before joining the traffic pattern.
Example Sentence 2
AWOS reported a temperature of 12 degrees Celsius and an altimeter setting of 29.92 at the destination airport.