Definition
An unscheduled aviation weather observation issued between routine hourly METAR reports when conditions at an airport change significantly. A SPECI is triggered by specific criteria such as a shift in wind direction or speed, a meaningful change in visibility, the onset or end of precipitation or thunderstorms, a change in ceiling or sky condition, or other safety-relevant changes. Its format is identical to a METAR.
Plain English
An out-of-cycle weather report for an airport, issued whenever the weather changes enough to matter to pilots, instead of waiting for the next hourly report.
Context Anchor
Seen in aviation weather reports when checking current airport weather before a flight or while monitoring weather near an airport.
Derivation
SPECI comes from the word 'special.' The point is that this report is issued in special circumstances — when something has changed — rather than on the regular schedule.
Why Pilots Care
Gives pilots the most current information needed for safe takeoff, landing, and route decisions when weather shifts quickly.
Grounding Statement
If the airport weather changes significantly before the next regular report is due, a SPECI may be issued to show the new conditions.
Intuition Check
SPECI does not mean a different kind of weather code to learn from scratch. It is a special, unscheduled report using the same general format as a METAR.
Example Sentence 1
A SPECI was issued at 1420Z when visibility dropped from 6 statute miles to 1 1/2 in moderate snow.
Example Sentence 2
A SPECI was issued after a sudden wind shift that exceeded the crosswind limit for the runway in use.