ATIS, AWOS, and ASOS

Picture this, you are landing at Podunk Airport. Naturally, you tune into the weather frequency to listen to the winds, altimeter, and other things before coming into land. The winds are broadcasted as 160 at 6 knots.

A couple minutes later, you are on final. Just as a final check, you plug the weather in one more time, and now it is reading 190 at 7 knots. It hasn't been another whole hour, so how did the weather reading change?

You could be listening to an AWOS or an ASOS!

All of these types of weather reporting systems can be tuned into on frequency and it will provide you: time of issuance, winds, altimeter, temperature, dewpoint, and cloud layers.

When you tune into an ATIS (automatic terminal information system), you will be provided with that information, and more, such as NOTAMs, frequencies, runway in use, and information letter. ATIS are found at larger, towered airports. They are either a digitized voice like an AWOS or ASOS, or are a human voice recording. The ATIS updates every hour, along with the METAR. AWOS, ASOS, or ATIS can be found at a towered airport, but ATIS seems to be the most common at your larger, Class Bravo airports.

AWOS (automated weather observation) and ASOS (automated surface observing system) both accomplish the same thing, and generally report the same items. However, ASOS are federally managed (FAA, NWS, etc), while AWOS can be operated and owned by local operators. In addition, AWOS and ASOS broadcasts are updated every minute, unlike the ATIS. ASOS broadcasts are also slightly more comphrehensive than AWOS.

Next time you are flying, take a note as to which airports have an AWOS, vs an ASOS, or an ATIS. And now you'll know the difference!

Happy Flying!