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Due to scheduled maintenance, many NCEI systems will be unavailable on Saturday, August 24 from 11:30 AM ET to 1:30 PM ET. We apologize for any inconvenience.

Automated Surface Observing System (ASOS)

Automated Surface Observing System (ASOS) units are automated sensor suites that are designed to serve meteorological and aviation observing needs. There are currently more than 900 ASOS sites in the United States. These systems generally report at hourly intervals, but also report special observations if weather conditions change rapidly and cross aviation operation thresholds.

ASOS serves as a primary climatological observing network in the United States. Not every ASOS is located at an airport; for example, one of these units is located at Central Park in New York City. ASOS data are archived in the Global Surface Hourly database, with data from as early as 1901.

  • 1-Minute ASOS Data
    These data are only available for ASOS stations. 
  • 5-Minute ASOS Data
    These data are only available for ASOS stations.
  • User Interface Page
    After agreeing to the regulations regarding data usage, you will be directed to select a Simplified or Advanced Option to obtain the data. Not recommended for large volumes of data.
  • Direct FTP Access
    Data by year; highly recommended for large volumes of data.