Inside AWOS And ASOS

kmaples

Wednesday, May 19, 2021 at 02:49 PM ET

Verified

Key Takeaways:

AWOS and ASOS stations primarily differ in ownership (ASOS by federal government; AWOS by state, local, or private entities) but utilize mostly the same sensors.
These automated weather stations are expensive to acquire ($50K-$200K) and maintain ($3K-$20K annually), requiring significant investment.
Some automated weather data, particularly cloud/ceiling and visibility, can be less accurate due to sensor limitations (e.g., single-point laser for clouds, short-range extrapolation for visibility).
Data update frequency varies: live radio reports are updated approximately once per minute, while other sources like online or FIS-B typically update every 20 minutes.

See a mistake? Contact us.

How many times have you heard a report like this? “Podunk Municipal airport, automated weather observation, 2347 Zulu. Weather, wind 050 at 12 knots, gust 23 knots. Visibility 7. Sky condition, clear below 12,000 feet. Temperature 29 Celsius, dew point 17 Celsius. Altimeter 30.00 inches of mercury. Remarks, intensive glider activity 20 miles north east of the airport, use caution.”

Anyone with more than a student certificate has heard these reports countless times. And yet the AWOS and ASOS system remains a bit of a mystery to many of us. Just tune the proper frequency and don’t worry about how the data is collected or how frequently it is updated. Who owns these stations anyway? And what is the difference between an AWOS and an ASOS station? Let’s take a close look at the mysterious world of automated weather reporting.