TAF
Terminal Aerodrome Forecast
A weather forecast for a specific airport, valid for typically 24 or 30 hours.
A TAF is a forecast of expected weather conditions at an airport (typically within a 5-statute-mile radius). TAFs are issued four times a day and cover the next 24–30 hours depending on the airport.
TAF format mirrors METAR but adds time periods with expected conditions and any forecast changes (BECMG, TEMPO, FM groups). Together, METAR (what's happening now) and TAF (what's expected) form the core weather decision data for VFR and IFR planning.
A TAF only exists for airports with sufficient operational activity. Smaller fields rely on the area forecast and nearby TAFs.
When it matters
TAF + METAR is the minimum weather check before any cross-country. Both are required reading at any DPE oral.