Definition
A Special Aviation Report (SPECI) is an unscheduled surface weather observation issued for an airport when conditions change significantly between the regular hourly METAR observations. SPECIs are triggered by specific criteria such as a shift in wind direction, a drop in visibility, the onset of thunderstorms, freezing precipitation, or a meaningful change in ceiling height. The format of a SPECI is identical to a METAR; only the report header differs.
Plain English
An off-schedule weather report from an airport, issued when the weather changes enough to matter before the next hourly report comes out.
Context Anchor
Seen in FIS-B data link weather, airport weather displays, and preflight or in-flight weather checks.
Derivation
The word 'special' comes from the Latin 'specialis,' meaning 'particular' or 'individual.' In this context, it signals a report issued for a particular event rather than as part of the regular hourly schedule.
Why Pilots Care
They give timely notice of weather changes that can affect takeoff, landing, or route safety so pilots can adjust plans quickly.
Grounding Statement
If the airport weather changes enough before the next regular report, a SPECI is the official update that fills the gap.
Intuition Check
“Special” does not mean optional or unusually important for its own sake. Here it means the report was triggered outside the normal schedule by a qualifying weather change.
Example Sentence 1
While en route, the pilot received a SPECI on the FIS-B uplink showing visibility at the destination had dropped from ten miles to two miles in mist.
Example Sentence 2
A SPECI was broadcast after a thunderstorm began at the alternate airport.