Definition
A SPECI is an unscheduled surface weather observation issued from an airport whenever conditions change significantly between the regular hourly METAR reports. It uses the same coded format as a METAR but is triggered by specific events such as a shift in wind, a drop in visibility, a change in ceiling, the onset or end of precipitation, thunderstorms, or other conditions defined by FAA and National Weather Service criteria.
Plain English
An off-schedule weather report from an airport, sent out when the weather changes enough to matter, instead of waiting for the next hourly report.
Context Anchor
Seen in aviation weather briefings, flight planning tools, and airport weather reports when conditions change between scheduled observations.
Derivation
From Latin specialis, meaning 'particular' or 'out of the ordinary.' The same root gives us 'special.' SPECI reports are issued for special, non-routine changes — not on the regular hourly schedule.
Why Pilots Care
A SPECI alerts pilots to sudden changes such as lowered visibility or wind shifts that may affect takeoff, landing, or alternate airport decisions.
Intuition Check
Do not read “special” as meaning optional or merely interesting. A SPECI is an official current weather observation issued outside the normal schedule because a reportable change occurred.
Example Sentence 1
The briefer mentioned a SPECI had just been issued at the destination showing visibility down to one mile in fog.
Example Sentence 2
The pilot checked the latest SPECI before deciding whether to continue the approach.