TAF Decoder

Paste any Terminal Aerodrome Forecast and get an instant plain-English breakdown of every group, including FM, BECMG, TEMPO, and PROB changes.

Try an example:

TAF vs METAR

FeatureTAFMETAR
PurposeForecast (future conditions)Observation (current conditions)
Coverage24-30 hours aheadSnapshot of current weather
IssuedEvery 6 hours (amended as needed)Every hour (SPECI when conditions change)
Change GroupsFM, BECMG, TEMPO, PROBNOSIG, BECMG, TEMPO (trend only)
TemperatureTX/TN (max/min forecasted)Current temp/dewpoint
AltimeterNot includedCurrent altimeter setting (QNH/A)

Need to decode a METAR? Use our free METAR Decoder

Common Weather Codes in TAFs

Weather codes in TAFs use the same format as METARs. Combine intensity prefixes (+/-) with phenomena (e.g., +TSRA = heavy thunderstorm with rain).

CodeMeaning
RARain
SNSnow
FGFog
BRMist (visibility > 1 km)
HZHaze
TSThunderstorm
SHShowers
DZDrizzle
GRHail (> 5mm)
GSSmall Hail (< 5mm)
FZFreezing
PLIce Pellets
ICIce Crystals
FUSmoke
SQSquall
FCFunnel Cloud / Tornado
+Heavy intensity
-Light intensity
VCIn the vicinity
BLBlowing

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How to Read a TAF

A Terminal Aerodrome Forecast (TAF) predicts weather conditions at an airport for the next 24-30 hours. Every TAF follows this structure:

TAF STATION ISSUE-TIME VALID-PERIOD WIND VISIBILITY WEATHER CLOUDS [FM/BECMG/TEMPO/PROB changes]
  • Station — 4-letter ICAO code (e.g., KJFK, EGLL, KORD)
  • Issue Time — DDHHMMz format in UTC (when the forecast was created)
  • Valid Period — DDHH/DDHH format showing start and end of forecast
  • Wind — Direction + speed in knots, with optional gusts (e.g., 27015G25KT)
  • Visibility — In statute miles (P6SM) or meters (9999 = 10km+)
  • Weather — Phenomena codes like RA (rain), SN (snow), TS (thunderstorm), FG (fog)
  • Clouds — Coverage + height in hundreds of feet AGL (e.g., BKN040 = broken at 4,000 ft)
  • FM (From) — Complete change in conditions at a specific time
  • BECMG (Becoming) — Gradual change over a 1-2 hour window
  • TEMPO (Temporary) — Brief fluctuations lasting under 1 hour
  • PROB (Probability) — Chance (30% or 40%) of conditions occurring

Unlike METARs that report current conditions, TAFs are forecasts. Pilots use them to plan fuel, alternates, and approach procedures before departure.

What is a TAF?

A Terminal Aerodrome Forecast (TAF) is an aviation weather forecast issued for the area within 5 statute miles of an airport’s runway complex. TAFs are created by National Weather Service meteorologists (in the US) and equivalent authorities worldwide.

TAFs are issued 4 times daily at 0000Z, 0600Z, 1200Z, and 1800Z. Each forecast covers a 24-hour period (30 hours for selected major airports). When significant weather changes are expected that differ from the current forecast, an amended TAF (TAF AMD) is issued.

Student pilots must learn to decode TAFs for the FAA Private Pilot Knowledge Test, Instrument Rating written exam, and Part 107 (Remote Pilot) exam. TAF questions appear frequently and test your ability to extract specific information about forecast conditions at particular times.

Frequently Asked Questions

What does TAF stand for?

TAF stands for Terminal Aerodrome Forecast. It is a weather forecast issued for the area within 5 statute miles of an airport runway complex. TAFs are issued every 6 hours and cover a 24 to 30-hour forecast period.

How do you read a TAF?

A TAF starts with the station identifier (ICAO code), issue time, and valid period. The base forecast includes expected wind, visibility, weather, and clouds. Change groups (FM, BECMG, TEMPO, PROB) indicate how conditions will evolve during the forecast period.

What is the difference between FM, BECMG, and TEMPO in a TAF?

FM (From) indicates a rapid and permanent change in conditions at a specific time. BECMG (Becoming) indicates a gradual change over a 1-2 hour period. TEMPO (Temporary) indicates fluctuating conditions expected to last less than an hour at a time and cover less than half the total period.

What does PROB30 mean in a TAF?

PROB30 indicates a 30% probability of the forecast conditions occurring. PROB40 means 40% probability. PROB groups are often combined with TEMPO (e.g., PROB30 TEMPO) to indicate a chance of temporary conditions. Probabilities below 30% or above 50% are not used in TAFs.

How far ahead does a TAF forecast?

Standard TAFs cover a 24-hour period, while amended TAFs at major airports may cover up to 30 hours. TAFs are issued 4 times per day at 0000Z, 0600Z, 1200Z, and 1800Z, and can be amended (AMD) at any time when conditions warrant.

Can I use TAFs for flight planning?

Yes, TAFs are essential for flight planning. The FAA requires pilots to check TAFs for departure, destination, and alternate airports. TAFs help you determine if weather minimums will be met for your planned approach and whether an alternate airport is required under FAR 91.169.

What does P6SM mean in a TAF?

P6SM means visibility is greater than 6 statute miles (the P stands for 'plus'). This is the maximum visibility reported in TAFs and METARs using the US format. In ICAO format, 9999 indicates visibility of 10 km or more.

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