Definition
An in-flight weather advisory issued by the National Weather Service to alert pilots of weather conditions that may be hazardous to aircraft, particularly those with limited capability due to lack of equipment, instrumentation, or pilot qualifications. AIRMETs cover phenomena less severe than those in a SIGMET, including moderate icing, moderate turbulence, sustained surface winds of 30 knots or more, widespread areas of ceilings less than 1,000 feet and/or visibility less than 3 miles, and extensive mountain obscuration.
Plain English
A weather warning sent out during flight to tell pilots about conditions that could be dangerous, especially for smaller aircraft or less-experienced pilots. It covers things like rough air, ice forming on the aircraft, strong winds, low clouds, and poor visibility.
Context Anchor
You will see Airmen's Meteorological Information during a weather briefing, in flight-planning tools, and on aviation weather displays before or during a flight.
Derivation
A blend of 'airmen' (pilots and crew) and 'meteorological' (relating to weather). The term was built to describe a weather message specifically for people flying aircraft.
Why Pilots Care
Helps pilots decide whether a planned route remains safe or requires changes before departure or en route.
Grounding Statement
If the weather along your planned route includes widespread conditions that could make the flight unsafe or difficult, an AIRMET is one way that warning is issued to pilots.
Intuition Check
Do not read “information” as casual background weather. In this term, it means an official aviation weather advisory that deserves a pilot’s attention before flight.
Example Sentence 1
During the briefing, the pilot noted an AIRMET for moderate turbulence below 12,000 feet along the route.
Example Sentence 2
Airmen's Meteorological Information bulletins are issued every six hours and updated as needed to reflect changing weather along common routes.