Definition
An in-flight weather advisory issued by the National Weather Service that warns pilots of weather phenomena which may affect aircraft safety but are less severe than those requiring a SIGMET. AIRMETs cover moderate icing, moderate turbulence, sustained surface winds of 30 knots or greater, widespread areas of ceilings less than 1,000 feet and/or visibility less than 3 miles, and extensive mountain obscurement.
Plain English
A weather warning for pilots that flags conditions serious enough to be a real concern for smaller or less-equipped aircraft, but not extreme. Things like rough air, icing, low clouds, low visibility, or strong surface winds.
Context Anchor
Pilots commonly see AIRMETs during a preflight weather briefing, on aviation weather websites, and in flight-planning apps.
Derivation
AIR from 'airman' (the pilot) and MET from 'meteorological' (weather-related). The name simply says what it is: weather information for pilots. 'Meteorological' comes from the Greek 'meteoron,' meaning 'thing high up in the air' — the same root as 'meteor.'
Why Pilots Care
Pilots review AIRMETs to assess whether conditions suit their aircraft and experience before departing.
Intuition Check
An AIRMET is not a clearance and it does not forbid flight. It is an official warning that certain weather hazards are expected or occurring over a broad area.
Example Sentence 1
During the briefing, the pilot noted an AIRMET for moderate icing between 8,000 and 14,000 feet and chose to file at 6,000 instead.
Example Sentence 2
An AIRMET for low ceilings prompted the pilot to file an alternate route.