Definition
The portion of a Terminal Aerodrome Forecast (TAF) that predicts weather phenomena expected to affect flight operations at the airport during the forecast period, including precipitation type and intensity, obstructions to visibility, and other meaningful weather events such as thunderstorms, fog, or freezing rain. It is reported using standard contractions in the same format as a METAR weather group.
Plain English
The part of a TAF that says what kind of weather is expected at the airport — rain, snow, fog, thunderstorms, and so on — and how strong it will be.
Context Anchor
Seen when reading a Terminal Aerodrome Forecast, or TAF, before a departure, arrival, or training flight.
Derivation
Forecast means to tell ahead of time. Significant comes from a Latin root meaning “a sign” or “something that matters.” In this phrase, it means weather worth noticing because it can affect flying.
Why Pilots Care
It flags weather that can create real hazards, directly affecting go/no-go decisions, route selection, and fuel planning.
Intuition Check
Significant does not mean “severe” here. It means weather important enough to include because it may matter to the flight.
Example Sentence 1
The TAF showed forecast significant weather of light rain and mist for the arrival window, so the pilot reviewed the approach minimums.
Example Sentence 2
Reviewing the forecast significant weather allowed the pilot to adjust the route and avoid icing conditions.