Aviation abbreviation

AO1

AO1 stands for “ASOS automated observation without precipitation discriminator (rain/snow)” (METAR usage). Got a NOTAM full of contractions? Paste it into the decoder.

Related abbreviations

AO2AOAAOAFAOBAOBFAOCAOCPAOEAOPA

Source: FAA Order JO 7340.2 Contractions. Not for operational use.