Definition
An AIRMET is a weather advisory issued by the National Weather Service for weather conditions that 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 reduced visibility below 3 statute miles, ceilings below 1,000 feet, and extensive mountain obscuration. They are particularly relevant to light aircraft and are issued on a scheduled basis every six hours, with unscheduled updates as conditions change.
Plain English
A weather warning aimed mainly at smaller aircraft, telling pilots about conditions like icing, bumpy air, low clouds, poor visibility, or strong surface winds that aren't extreme but still matter — especially if you're flying a light plane.
Context Anchor
Pilots encounter AIRMETs during preflight weather planning, weather briefings, and in-flight weather updates when checking whether a route crosses an area of concerning weather.
Derivation
From 'airman' (a person who flies) and 'meteorological' (relating to weather), which comes from the Greek 'meteoron' meaning 'thing high up in the air.' The name simply signals that this is weather information for the people doing the flying.
Why Pilots Care
Allows pilots to decide whether to delay departure, change altitude or route, or cancel to avoid weather that reduces safety margins even though it is not extreme.
Intuition Check
Do not treat an AIRMET as just a routine weather note. It is a safety advisory about specific weather conditions that may matter to your flight.
Example Sentence 1
During preflight, the pilot noted an AIRMET for moderate icing between 6,000 and 12,000 feet and chose a lower cruising altitude to stay clear of it.
Example Sentence 2
An AIRMET for IFR conditions covering the entire state led the VFR pilot to postpone the flight until evening.