Aircraft Systems

ATIS, AWOS, and ASOS Explained

Understand the difference between ATIS, AWOS, ASOS, and METARs, and learn how pilots use airport weather broadcasts before flight.

Diego Suarez 3 min read

ATIS, AWOS, and ASOS are all airport information sources, but they do not do the same job. Once you separate them by purpose, the acronyms become much easier to use in the airplane.

ATIS gives airport and weather information at towered airports. AWOS and ASOS are automated weather systems. METARs are coded weather reports pilots commonly use during preflight planning.

For student pilots, the practical question is: what should I listen to, when should I listen to it, and what should I do with the information?

ATIS

ATIS stands for Automatic Terminal Information Service. It is a continuous broadcast used at towered airports. It usually includes weather, active runways, approaches in use, operational notes, and instructions such as "advise on initial contact you have information Alpha."

The letter identifier matters. If you tell tower you have "Information Charlie," the controller knows which version you heard. If the airport has already moved to "Information Delta," you may be missing newer information.

ATIS is useful before taxi and before arriving. On departure, it helps you plan runway, altimeter setting, wind, and airport notes. On arrival, it helps you prepare for the expected runway and approach environment before talking to the controller.

AWOS

AWOS stands for Automated Weather Observing System. It is an automated system that measures and broadcasts weather information, often at smaller airports.

Depending on the AWOS type, it may report wind, visibility, temperature, dew point, altimeter setting, sky condition, precipitation, thunderstorm detection, or other weather elements.

The important student-pilot point is that AWOS is weather-focused. It does not normally give the full airport operational picture you expect from ATIS. It may tell you the wind and altimeter, but not which runway tower is using because there may be no tower.

ASOS

ASOS stands for Automated Surface Observing System. Like AWOS, it provides automated weather information. ASOS systems also support broader weather reporting and forecasting functions.

From the pilot's perspective, ASOS and AWOS can feel similar because both may be accessed by radio or phone and both provide current airport weather. The exact reported elements depend on the station and equipment.

When flying to a non-towered airport, ASOS or AWOS can be one of your best tools for choosing a runway, setting the altimeter, and checking whether conditions match your plan.

METAR vs. ATIS, AWOS, and ASOS

A METAR is a coded weather report. It is usually used during preflight planning or in cockpit weather displays. It gives weather data in a standard format.

ATIS is a broadcast that may include METAR-based weather plus airport-specific operational information.

AWOS and ASOS are automated weather observation systems that broadcast current conditions and may feed reported weather products.

So the difference is not just content. It is how the information is produced, delivered, and used.

How to Use Them in Training

Before departure from a towered airport, listen to ATIS before calling clearance, ground, or tower unless local procedures say otherwise. Write down the identifier, wind, visibility, ceiling, altimeter, runway, and any notes.

Before arriving at a towered airport, listen early enough that you are not copying information while already busy with descent, pattern entry, or approach setup.

At a non-towered airport, use AWOS or ASOS to support runway selection and weather awareness. Then compare that information with what you see outside and what other traffic reports on the CTAF.

If the broadcast and the real-world picture disagree, slow down and sort it out. Wind can shift, visibility can vary across the field, and automated systems can occasionally report conditions that need pilot judgment.

What to Copy

You do not need to write a novel. A useful note might include:

  • Identifier, if ATIS.
  • Wind.
  • Visibility and ceiling.
  • Altimeter.
  • Runway or approach in use.
  • Important airport notes.

Then use the information. Set the altimeter. Brief the runway. Think about crosswind. Compare the reported conditions to your personal minimums.

These systems are not just acronyms for a written test. They are practical tools for reducing cockpit workload and making better decisions before takeoff and landing.

Official References

Ground instruction

Need help applying this to your training?

Use this guide as a starting point, then bring the confusing parts to a focused ground lesson. Diego works with Louisville-area and remote students on FAA knowledge, oral-prep, and practical training decisions.

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