Example TAF
TAF KJFK 251730Z 2518/2624 21012KT P6SM SCT040 BKN080
TEMPO 2520/2602 4SM TSRA BKN030CB
FM260200 31008KT P6SM FEW050
BECMG 2612/2614 18010KT SCT030
| Element | Meaning |
|---|---|
| KJFK | Airport: JFK International |
| 251730Z | Issued on the 25th at 17:30 UTC |
| 2518/2624 | Valid from 25th 18:00Z to 26th 24:00Z (30 hours) |
| 21012KT | Initial: wind from 210 at 12 knots |
| TEMPO 2520/2602 | Temporarily between 25th 20Z and 26th 02Z |
| FM260200 | From 26th 02:00Z, new conditions begin |
| BECMG 2612/2614 | Becoming, gradually changing between 12Z and 14Z on the 26th |
TAF Change Groups
TAFs use special keywords to describe how weather will change during the forecast period:
FM (From)
Indicates an immediate and permanent change in conditions at the specified time. Everything after FM replaces the previous forecast. Format: FMDDHHmm
TEMPO (Temporary)
Temporary fluctuations expected to last less than an hour at a time, occurring during the specified period. The base conditions still apply between temporary changes. Format: TEMPO DDHH/DDHH
BECMG (Becoming)
A gradual change expected to occur during the specified period. Once the change is complete, the new conditions persist. Format: BECMG DDHH/DDHH
PROB (Probability)
Indicates a probability (30% or 40%) of the forecast conditions occurring. Only PROB30 and PROB40 are used; conditions with higher or lower probability are handled differently.
Key Differences: TAF vs. METAR
| Feature | METAR | TAF |
|---|---|---|
| Type | Observation (current) | Forecast (future) |
| Duration | Snapshot at a point in time | 24-30 hour forecast |
| Frequency | Every 30-60 minutes | Every 6 hours (with amendments) |
| Change groups | None | FM, TEMPO, BECMG, PROB |
| Temperature | Included | Not always included |
| Altimeter | Included | Not included |
Flight Planning Tip
Always cross-reference TAF with METAR. A TAF is a forecast and may not match actual conditions. Check the latest METAR before departure and at your destination for current reality.TAF Validity Periods
- Standard TAF - 24-hour validity, issued 4 times daily
- Extended TAF - 30-hour validity at major airports
- AMD - Amended TAF issued when significant changes invalidate the current forecast
- COR - Corrected TAF to fix errors in the issued forecast