Definition
A network of automated airport-based stations that continuously measure local weather conditions and broadcast the current observation to pilots by radio and, at many sites, by telephone. A typical AWOS reports wind direction and speed, visibility, cloud height, temperature, dew point, altimeter setting, and density altitude, with higher-level versions adding precipitation, thunderstorm, and runway-specific data. Reports are updated about once per minute and are issued without human input.
Plain English
An unmanned weather station at an airport that takes constant readings and reads the latest conditions out loud over the radio so pilots can hear what the weather is doing right now at that field.
Context Anchor
Pilots commonly listen to AWOS before takeoff, before landing, or while planning a flight to check the latest weather at a specific airport.
Derivation
The name is descriptive: 'automated' (no human observer), 'weather observing' (it measures conditions), 'system' (a coordinated set of sensors and a broadcast unit). Knowing this reminds you the report comes from machines reading sensors — not a person looking at the sky — which is useful when the report disagrees with what you can see.
Why Pilots Care
Provides essential real-time weather data at airports without a control tower or human weather observer, helping pilots make safe go/no-go decisions.
Intuition Check
AWOS is not a forecast. It reports the weather being measured at or near the airport now.
Example Sentence 1
Ten miles out, he tuned the AWOS frequency and noted the wind favored runway 27 with a ceiling of 2,500 feet.
Example Sentence 2
The AWOS at the remote airport reported low visibility, prompting the pilot to delay the flight.