How to Read a TAF for Part 107

A METAR tells you what the weather is at an airport. A TAF tells you what it is forecast to be. The FAA's Remote Pilot Study Guide describes the terminal aerodrome forecast as covering a 5 statute mile radius around an airport, valid for 24 or 30 hours, issued four times a day at 0000Z, 0600Z, 1200Z and 1800Z, and written with the same codes as the METAR. If you can read a METAR, you can read most of a TAF.

What does a TAF look like?

Here is an example in the format the study guide describes. It is illustrative, not a real forecast:

TAF KDEN 051130Z 0512/0612 18010KT P6SM SCT060
  FM051800 22015G25KT P6SM BKN080
  TEMPO 0520/0523 3SM TSRA BKN040CB
  FM060200 20008KT P6SM SKC

How do you decode it line by line?

TAF KDEN 051130Z. A routine forecast (an amended one says TAF AMD) for Denver, issued on the 5th at 1130 UTC. Times in a TAF are always UTC.

0512/0612. The valid period: from the 5th at 1200Z to the 6th at 1200Z, 24 hours. The study guide notes that a period ending at midnight is written as 24, so 0900/0924 runs to midnight on the 9th.

18010KT P6SM SCT060. The opening conditions. Wind from 180° true at 10 knots, as in a METAR. P6SM means visibility greater than 6 statute miles. Scattered clouds at 6,000 feet AGL.

FM051800 22015G25KT P6SM BKN080. "From" the 5th at 1800Z, a new set of conditions replaces the old one: wind from 220° at 15 knots gusting 25, broken clouds at 8,000 feet. The study guide says FM is used when a rapid and significant change, usually within an hour, is expected.

TEMPO 0520/0523 3SM TSRA BKN040CB. Temporarily, between 2000Z and 2300Z, visibility 3 statute miles in thunderstorms with moderate rain, broken cumulonimbus at 4,000 feet. The study guide describes TEMPO as temporary fluctuations expected to last less than an hour at a time.

FM060200 20008KT P6SM SKC. From the 6th at 0200Z, light wind and clear skies.

What is different from a METAR?

• Change groups. FM, TEMPO and PROB30 have no METAR equivalent. PROB30 gives a 30 percent probability of thunderstorms or precipitation in a period, and the study guide says it is not used in the first 6 hours of a 24-hour forecast.
• Clouds. The study guide says only cumulonimbus (CB) is forecast in the sky condition, while a METAR can also report towering cumulus.
• No temperature or altimeter. A TAF forecasts what affects flight conditions, not the numbers you set or use for density altitude. For those, use the latest METAR and the density altitude calculator.

How do you turn a TAF into a go or no-go?

Compare each period with the limits in 14 CFR §107.51: at least 3 statute miles of visibility and at least 500 feet below clouds. In the example, the morning is fine. From 1800Z the gusts to 25 knots are a practical limit for many small drones. The TEMPO period brings thunderstorms, which no remote pilot should be flying in, so the sensible plan is to finish before 2000Z or wait for the 0200Z clearing.

What the exam asks about TAFs

Weather sources are ACS task UA.III.A, and the TAF has its own element, UA.III.A.K3, right after METARs in K2. Expect a TAF excerpt with a question about one period: what the wind or visibility is at a given time, what a TEMPO or FM line means, or when the forecast ends. Convert the time carefully: everything is UTC. The METAR guide covers the shared codes, and the thunderstorm post covers why a TSRA line ends the day.