AIRMET stands for Airmen’s Meteorological Information. It is defined by ICAO as “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 or sub-area thereof.”
SIGMET stands for Significant Meteorological Information. It is defined by ICAO as “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 aircraft operations.”
The difference between these two hangs on “the level or altitude of aircraft operations and the severity of the weather phenomena.” In other words;
- AIRMET is mainly concerned with low level aircraft operations, while SIGMET accommodates all aircraft operations;
- AIRMET captures less severe weather phenomena than SIGMET; and
- Both, however, warn Pilots of potentially hazardous weather conditions and give concise description of the phenomena in abbreviated plain language.
REFERENCES
ICAO Annex 3
