Description

An AIRMET is a message containing information issued by a meteorological watch office concerning the occurrence or expected occurrence of specified en-route weather phenomena which may affect the safety of low-level aircraft operations and which was not already included in the forecast issued for low-level flights in the flight information region concerned.

In this context, low-level operations means flight below FL100 (or below FL150 or higher in mountainous areas).

An AIRMET gives a concise description of the phenomena in abbreviated plain language.

The following are examples of weather phenomena that may be described in an AIRMET:

• Surface wind speed above 30 kt
• Surface visibility below 5000 m
• Thunderstorm
• Mountain obscuration
• Broken or overcast Cloud with base below 1000 ft
• Cumulonimbus (Cb) clouds
• Moderate or severe icing
• Moderate or severe turbulence
• Moderate or severe Mountain Waves

Related Articles

• Weather Forecast
• Weather Observations at Aerodromes
• SIGMET

Further Reading

ICAO Annex 3 Chapter 7