How to Decode a TAF
A TAF is the weather forecast pilots use to decide whether a flight is legal, practical, and smart. METAR tells you what is happening now; TAF tells you what is expected at an airport over the next 24 to 30 hours. The skill is not memorizing codes. The skill is building a timeline: what conditions exist now, when they change, and whether any temporary or probability groups create operational risk during your arrival window.
Prerequisites
- → Basic METAR decoding knowledge
- → Departure, destination, and alternate airports selected
- → Planned departure and arrival times in UTC
- → Personal minimums or company weather minimums
Step-by-Step
- 1
Confirm station and issue time
Start with the ICAO station and the issue group. Example: TAF KDEN 261130Z means the forecast was issued for Denver at 1130 UTC on the 26th. If the issue time is old, look for an amended TAF before using it for planning.
- 2
Read the valid period
The group 2612/2718 means the forecast is valid from the 26th at 1200 UTC until the 27th at 1800 UTC. Compare that window with your planned ETA. A perfect TAF outside your arrival time is useless.
- 3
Build the baseline forecast
The first wind, visibility, weather, and cloud groups are the starting conditions for the valid period. Decode them exactly like a METAR: wind direction and speed, visibility, weather codes, and cloud heights in hundreds of feet AGL.
- 4
Split the forecast at FM groups
FM means from, and it creates a new forecast segment. FM261800 22012KT P6SM SCT050 means from the 26th at 1800 UTC, the forecast changes to winds 220 at 12 kt, visibility greater than 6 SM, and scattered clouds at 5,000 ft.
- 5
Treat TEMPO as a risk window
TEMPO means temporary conditions expected for less than half of the stated period. TEMPO 2618/2622 2SM TSRA BKN020CB does not mean the weather is always bad, but it does mean thunderstorms and low ceilings are credible during that window.
- 6
Read PROB groups conservatively
PROB30 means a 30 percent probability of the listed condition. For training flights, new instrument students, or marginal alternates, treat PROB30 thunderstorms, freezing rain, or low IFR as a serious planning constraint.
- 7
Compare against legal and personal minima
For IFR, check destination and alternate requirements around ETA. For VFR, compare ceiling, visibility, wind, gusts, precipitation, and convective risk against your real skill level, not just the legal minimum.
- 8
Cross-check with METAR, radar, and PIREPs
A TAF is a forecast, not proof. If the current METAR and pilot reports already disagree with the TAF trend, slow down and look for updated guidance before launching.
Common Mistakes
- × Reading only the first line and missing later FM or TEMPO groups
- × Treating TEMPO as if it will not affect you because it is temporary
- × Forgetting that cloud heights in TAFs are AGL, not MSL
- × Using local time mentally when all TAF times are UTC
- × Ignoring gusts and crosswind even when ceiling and visibility look legal
Pro Tips
- ★ Write the TAF as a timeline with UTC blocks before making a go/no-go call
- ★ Mark your ETA plus one hour on the forecast timeline
- ★ For student pilots, treat TEMPO thunderstorms and low IFR as a no-go until discussed with a CFI
- ★ Use TAF trends to choose a better alternate, not just to justify the original plan
Conclusion
A good TAF briefing turns a wall of coded text into a timeline. If you can answer three questions -- what will it be at departure, what will it be at arrival, and what could temporarily make it worse -- you are using the forecast like a pilot instead of reading it like a vocabulary test.
FAQ
How is a TAF different from a METAR?
A METAR is an observation of current airport weather. A TAF is a forecast for future conditions at or near the airport.
Are TAF times local or UTC?
TAF times are UTC. Convert to local time only after you understand the UTC forecast window.
What does TEMPO mean in a TAF?
TEMPO means temporary conditions expected during the stated time window, generally lasting less than half that period.