VOLMET, or meteorological information for aircraft in flight, is the term applied to a worldwide network of radio stations that broadcast TAF, SIGMET and METAR reports on shortwave frequencies. Reports are sent using automated voice transmissions, in the upper sideband or J3E mode. As the name suggests, pilots on international air routes use these transmissions to determine what procedures to use for descent, approach, and landing, such as a visual approach or an instrument approach and the correct approach heading.
