top of page

ATIS, AWOS, and ASOS in Aviation: What Pilots Need to Know

Weather reporting and communication systems are critical to aviation safety. Pilots depend on accurate, timely, and consistent information to make decisions about takeoff, enroute operations, and landing. Three common systems provide this information in the United States: ATIS (Automatic Terminal Information Service), AWOS (Automated Weather Observing System), and ASOS (Automated Surface Observing System).


Though they share similarities, each system serves a different role in supporting pilots and air traffic controllers.



Study this full length lesson (video, podcast, flashcards, and quiz) here: Full Length Lesson >


ATIS – Automatic Terminal Information Service

  • Purpose: ATIS provides continuous, recorded broadcasts of essential non-control information at busier airports. Its goal is to reduce radio congestion between pilots and air traffic control by automatically delivering routine information.

  • Content includes:

    • Current weather (winds, visibility, ceiling, temperature, dew point, altimeter setting).

    • Runway(s) in use.

    • Approach information (e.g., ILS, RNAV).

    • Notices to Air Missions (NOTAMs) relevant to the airport.

    • Frequency and communication reminders.

  • How it’s delivered: Pilots tune into a specific ATIS frequency before contacting clearance delivery or ground. Each update is given a letter (e.g., “Information Bravo”). Pilots reference this letter when checking in, so ATC knows they have the latest data.

  • Aviation role: ATIS reduces controller workload, speeds up pilot communication, and ensures all arriving and departing pilots have the same situational awareness.


AWOS – Automated Weather Observing System

  • Purpose: AWOS provides real-time, automated weather observations, primarily at smaller airports that may not have full-time weather observers.

  • Capabilities (depending on AWOS type):

    • Wind speed, direction, and gusts.

    • Visibility and cloud height.

    • Temperature, dew point, and altimeter setting.

    • Precipitation and weather type (some advanced AWOS can detect freezing rain, snow, or thunderstorms).

  • How it’s delivered: Pilots can receive AWOS information by tuning into a local frequency or via a phone number. Updates are typically broadcast every minute, giving highly current conditions.

  • Aviation role: AWOS provides up-to-date weather for pilots operating at smaller airports, supporting both VFR and IFR decision-making.


ASOS – Automated Surface Observing System

  • Purpose: ASOS is the primary surface weather observing network in the U.S., operated jointly by the FAA, NWS, and DoD. It provides comprehensive, continuous, and standardized weather reports.

  • Capabilities:

    • Wind speed, direction, and gusts.

    • Temperature, dew point, and altimeter setting.

    • Cloud coverage and ceiling.

    • Visibility and obstructions to vision (fog, haze, smoke).

    • Precipitation type and accumulation.

    • Thunderstorm and lightning detection.

  • How it’s delivered: Pilots can access ASOS data through radio frequencies, phone numbers, or weather dissemination systems. Reports update at least once per hour (METARs), but conditions like rapidly changing visibility or thunderstorms will trigger special updates (SPECI reports).

  • Aviation role: ASOS provides the most comprehensive, standardized reports, often forming the basis for official METARs and TAFs used in flight planning nationwide.


Key Differences Between ATIS, AWOS, and ASOS

  • ATIS: Focuses on airport-specific operational information at busier airports, including weather, runways, and NOTAMs, broadcast continuously on a loop.

  • AWOS: Provides automated, real-time weather observations at smaller airports, usually updating every minute.

  • ASOS: The most advanced and standardized system, forming the backbone of official weather reporting in aviation.


Conclusion

While ATIS, AWOS, and ASOS all deliver vital information to pilots, they serve different purposes: ATIS for reducing ATC workload and providing operational info, AWOS for real-time local airport weather, and ASOS for comprehensive national weather reporting. Pilots who understand the differences can better prepare for every stage of flight, from preflight planning to final approach.



Study Full Aviation Courses:

wifiCFI's full suite of aviation courses has everything you need to go from brand new to flight instructor and airline pilot! Check out any of the courses below for free:


Study Courses:


Checkride Lesson Plans:


Teaching Courses:



 
 
bottom of page