Plain English Meaning

Automated weather stations at airports that constantly measure local conditions and broadcast them so pilots can hear current weather before takeoff or landing.

Full Definition

ASOS and AWOS are networks of automated weather stations located at airports that continuously measure surface weather conditions and broadcast the results to pilots. They report items such as wind direction and speed, visibility, cloud height, temperature, dew point, altimeter setting, and precipitation. Reports are transmitted by a dedicated radio frequency and, at most , by telephone. ASOS is the more capable jointly operated by the , NWS, and , while AWOS is a family of FAA-operated with varying levels of capability (AWOS-A, AWOS-1, AWOS-2, , etc.).