Free tool
TAF decoder
Paste a terminal forecast and read it as a timeline. Each period shows whether it replaces, amends, or temporarily overlays the forecast.
or
or
Try an example
Paste a forecast above, or try one of the examples. For the weather happening right now rather than later, use the METAR decoder.
How TAF periods work
- A forecast, not an observation
- A METAR tells you what the weather is right now. A TAF tells you what it will be over the next 24 to 30 hours. It opens with a base forecast, then a sequence of groups that change it.
- FM: a clean break
- FM (from) restates the forecast in full. Everything before it stops applying, and the new conditions take over completely. If a group does not mention clouds, it means the forecast has no clouds from that point on.
- BECMG: a gradual shift
- BECMG (becoming) lists only what changes. Anything it does not mention carries on from the period before it. So BECMG with just a wind group means the wind is shifting but everything else stays the same.
- TEMPO and PROB: temporary conditions
- TEMPO describes conditions that come and go without replacing the forecast. PROB gives a probability that something will happen. PROB40 TEMPO is one period, not two: a 40% chance of temporary conditions.
- Times
- A TAF gives the day of the month and the hour in UTC. The times are shown as written. Converting to local time would require knowing the month, which the TAF does not carry.
Want the weather now instead?
A TAF is a forecast. The METAR decoder reads the current observation for the same field, group by group, with the flight category.
Open the METAR decoderAnd the wind on each runway
The crosswind calculator reads the current METAR and gives the headwind and crosswind for every runway at the field.
Open the crosswind calculatorNot a substitute for an official pre-flight weather briefing.