TAF decoder

Paste any raw TAF, or pull the current one for an airport, to see each forecast period and what every group means.

or paste a TAF

TAF structure reference

The groups that are specific to forecasts. Wind, visibility, weather and cloud use the same codes as a METAR (see below).

TAF: Terminal Aerodrome Forecast, usually valid 9–30 hours.
AMD / COR: Amended forecast / corrected forecast.
ddhhmmZ: Issue time: day of month, hours and minutes UTC.
ddhh/ddhh: Validity or change period: from day/hour until day/hour UTC. 24 means midnight at the end of that day.
FMddhhmm: From: a complete change at this time. Everything before is replaced.
BECMG: Becoming: a gradual change during the period, then lasting. Elements not mentioned stay the same.
TEMPO: Temporarily: spells under 1 hour each, together less than half the period.
INTER: Intermittent (Australia): spells under 30 minutes.
PROB30 / PROB40: 30% or 40% chance. Can be combined with TEMPO.
TXnn/ddhhZ: Forecast maximum temperature and when it occurs (TN = minimum, M = minus).
WShhh/dddffKT: Low-level wind shear up to hhh hundred ft, with the wind at that height.
NSW: No significant weather: ends the weather forecast earlier.
P6SM: Visibility more than 6 statute miles (US/Canada).
QNHnnnnINS: Lowest altimeter setting expected (US military).
6IhhhT / 5BhhhT: Icing / turbulence layer: type, base in hundreds of ft, thickness in thousands of ft (military).
NXT FCST BY: Time by which the next forecast will be issued (Canada).
AMD NOT SKED: No routine amendments, usually because observations are missing.

Weather, cloud and other codes

Every code, abbreviation and group used in a METAR, grouped by topic.

Report basics

METAR: Routine aviation weather report, issued hourly (or half-hourly) from a fixed station.
SPECI: Special report issued between routine METARs when conditions change significantly.
ddhhmmZ: Observation time: day of month, hour and minute in UTC, e.g. 142050Z.
AUTO: Fully automated observation, no human oversight or augmentation.
COR / CCA: Correction to a previously transmitted report (CCA = first correction, CCB second…).
RTD: Delayed (retarded) report, transmitted late.
NIL: No report available.
RMK: Marks the start of remarks — supplementary, often station-specific, detail after the coded body.
NOSIG: No significant change expected in the next 2 hours.
CAVOK: Ceiling And Visibility OK — visibility ≥ 10 km, no cloud below 5,000 ft, no significant weather.
/ / / /: Slashes replace any value the station could not observe or measure.
M: On its own (US automated stations): the whole field is missing.

Wind

dddffKT: Wind direction (degrees true) and speed in knots, e.g. 27012KT = 270° at 12 kt.
VRB: Variable wind direction (light and shifting wind, usually under 6 kt).
G: Gust indicator, e.g. 27018G28KT = gusting to 28 kt.
P: More than, e.g. 270P99KT = over 99 kt.
E: Prefix for an estimated wind (Mexico), e.g. E21010KT.
dddVddd: Wind direction varying between the two given headings.
00000KT: Calm.
KT / MPS / KMH: Units — knots, metres per second, kilometres per hour.
WS: Wind shear, e.g. WS ALL RWY or WS R28.

Visibility & RVR

9999: 10 km or more visibility.
0000–9000: Prevailing visibility in metres, e.g. 0800 = 800 m.
NDV: No directional variation — the automated sensor cannot assess visibility by direction.
1500SW: Minimum visibility and its direction, e.g. 1,500 m towards the southwest.
SM: Statute miles (used in North American reports), e.g. 1 1/2SM.
M1/4SM: Less than 1/4 statute mile visibility.
P6SM: More than 6 statute miles (TAF).
10KM: Visibility in kilometres (used by some stations).
R28/0600: Runway visual range for runway 28 is 600 m.
R28/0600V1000: RVR varying between 600 and 1,000 m.
M / P (RVR): Less than the lowest / more than the highest value the system can measure, e.g. R28/P2000.
U / D / N: RVR tendency: up (improving), down (deteriorating), no change.
FT: RVR given in feet instead of metres (North America), e.g. R06/2400FT.

Weather phenomena

Intensity & proximity

+ / -: Heavy / light. No prefix means moderate.
VC: In the vicinity of the station (5–10 nm away).
RE: Recent weather prefix, e.g. RERA = rain ended recently.
NSW: No significant weather (trend/TAF): previous weather has ended.

Descriptors

MI: Shallow.
BC: Patches.
PR: Partial.
DR: Drifting.
BL: Blowing.
SH: Showers.
TS: Thunderstorm.
FZ: Freezing.

Precipitation

RA: Rain.
SN: Snow.
DZ: Drizzle.
SG: Snow grains.
GR: Hail.
GS: Small hail / snow pellets.
PL: Ice pellets.
IC: Ice crystals.
UP: Unknown precipitation.

Obscuration

BR: Mist.
FG: Fog.
HZ: Haze.
FU: Smoke.
DU: Widespread dust.
SA: Sand.
VA: Volcanic ash.
PY: Spray.

Other phenomena

PO: Dust/sand whirls.
SQ: Squall.
FC: Funnel cloud (tornado/waterspout).
SS: Sandstorm.
DS: Duststorm.

Sky condition

FEW: 1–2 oktas of cloud cover (few).
SCT: 3–4 oktas of cloud cover (scattered).
BKN: 5–7 oktas of cloud cover (broken).
OVC: 8 oktas of cloud cover (overcast).
hhh: Cloud base in hundreds of feet, e.g. BKN012 = broken at 1,200 ft.
VV: Vertical visibility — sky obscured, value is vertical visibility into the obscuration.
NSC: No significant cloud.
NCD: No cloud detected (automated station).
CLR / SKC: Clear skies.
CB: Cumulonimbus — thunderstorm cloud.
TCU: Towering cumulus.
///: In a cloud group: amount, height or type not observed by the automated sensor, e.g. BKN025/// or ///CB.
CB/SE: Cumulonimbus seen in the given direction(s) (Central America/Caribbean).
3AC100: Oktas, cloud type and base, e.g. 3 oktas of altocumulus at 10,000 ft (used in some regions and remarks).

Pressure & temperature

QNH / Qxxxx: Altimeter setting in hectopascals (hPa).
Axxxx: Altimeter setting in inches of mercury (inHg), used in North America.
QFE: Pressure at aerodrome elevation. Russia/CIS: QFE745/0993 = 745 mmHg / 993 hPa.
TT/TT: Temperature/dew point in °C. An "M" prefix means sub-zero, e.g. M02 = −2°C.
RHnn: Relative humidity in % (some countries).

Trend & forecast (TAF-style groups also seen in METAR trend)

BECMG: Becoming — a permanent change to the conditions that follow.
TEMPO: Temporary — conditions expected for less than half of the stated period.
PROBnn: Probability (%) that the conditions which follow will occur.
FM / TL / AT: From / Until / At — change-group timing, followed by HHMM (METAR trend) or ddHHMM (TAF).

Runway state (Europe / Russia)

Rrr/ECeeBB: Runway rr: deposit E, extent C, depth ee, braking BB, e.g. R24/290250.
E — deposit: 0 clear and dry · 1 damp · 2 wet / water patches · 3 rime or frost · 4 dry snow · 5 wet snow · 6 slush · 7 ice · 8 compacted snow · 9 frozen ruts.
C — extent: 1 up to 10% · 2 11–25% · 5 26–50% · 9 51–100% of the runway covered.
ee — depth: 00 under 1 mm · 01–90 mm · 92–97 = 10–35 cm · 98 40 cm or more · 99 runway not operational.
BB — braking: 01–90 friction coefficient (0.01–0.90) · 91 poor · 92 medium/poor · 93 medium · 94 medium/good · 95 good · 99 unreliable.
CLRD: Runway contamination cleared, e.g. R24/CLRD70.
R88 / R99: All runways / repetition of the previous runway state report.

Regional & military groups

Wtt/Sn: Sea-surface temperature (°C) and sea state (0 calm … 9 phenomenal), offshore/coastal stations.
Wtt/Hhhh: Sea-surface temperature and significant wave height in decimetres.
BLU … RED: Military colour state from cloud base and visibility: BLU, WHT, GRN, YLO1, YLO2, AMB, RED.
BLACK: Prefix to a colour state: aerodrome unusable for reasons other than weather.
QBBnnn: Cloud base in metres (Russia/CIS), e.g. QBB100 = 100 m.
MT OBSC: Mountains obscured.
OBST OBSC: Obstacles obscured.
R24/17004MPS: In remarks: wind at a specific runway (Russia/CIS).

US & Canadian remarks

Station & sensors

AO1: Automated station without a precipitation discriminator.
AO2: Automated station with a precipitation discriminator (rain vs snow).
AO2A: Automated observation augmented by a human observer.
$: Station needs maintenance.
TSNO: Lightning detector not available.
FZRANO: Freezing-rain sensor not available.
PWINO: Present-weather sensor not available.
PNO: Precipitation gauge not available.
RVRNO: RVR missing.
SLPNO: Sea level pressure not available.

Coded groups

SLPppp: Sea level pressure, e.g. SLP132 = 1013.2 hPa.
Tsttt sddd: Temp/dew point to 0.1 °C, 1 = negative, e.g. T01061017 = 10.6 / −1.7 °C.
1snnn / 2snnn: 6-hour maximum / minimum temperature.
4snnnsnnn: 24-hour maximum and minimum temperature.
5appp: 3-hour pressure tendency (a) and change in 0.1 hPa.
Prrrr: Precipitation in the past hour, hundredths of an inch.
6rrrr / 7rrrr: 3/6-hour and 24-hour precipitation; 6//// = amount indeterminate.
4/sss: Snow depth on the ground in inches.
Innnn: Ice accretion over 1 (I1), 3 (I3) or 6 (I6) hours, hundredths of an inch.
RAB05 / SNE43: Precipitation began (B) / ended (E) at the given minute or hhmm.
PK WND: Peak wind, e.g. PK WND 28045/15 = 280° at 45 kt at :15.
WSHFT: Wind shift at the given time, FROPA if caused by a front.
VIS 1V2: Variable visibility between the two values.
CIG 005V010: Variable ceiling between the two heights (hundreds of ft).
PRESRR / PRESFR: Pressure rising / falling rapidly.

Canada

SC4AC2: Cloud type and opacity (oktas) per layer, lowest first.
SOG nn: Snow on ground, cm.
DENSITY ALT: Density altitude in feet.
PCPN: Precipitation amount, e.g. PCPN 1.2MM PAST HR.
LAST STFD OBS: Last staffed observation of the day.
TR: Trace amount of the named cloud type.

Remark abbreviations

ACC: Altocumulus castellanus.
ACSL: Altocumulus standing lenticular (wave cloud).
ALP: Airport location point.
ALQDS: All quadrants (in every direction).
ALSTG: Altimeter setting.
ALT: Altitude.
AMT: Amount.
AND: And.
APCH: Approach.
ARND: Around.
AT: At.
BASE: Cloud base.
BINOVC: Breaks in overcast.
BIRD: Bird activity.
BKN: Broken (5–7 oktas).
BTN: Between.
CBMAM: Cumulonimbus mammatus.
CCSL: Cirrocumulus standing lenticular.
CEILOMETER: Cloud-height sensor.
CHINO: Sky condition at the secondary location not available.
CIG: Ceiling (lowest broken or overcast layer).
CLD: Cloud.
CONS: Continuous.
CONTRAILS: Condensation trails from aircraft visible.
CVCTV: Convective.
DATA: Data.
DENSITY: Density (as in density altitude).
DIST: Distant.
DP: Dew point.
DSIPTD: Dissipated.
DSNT: Distant — more than 10 sm (16 km) from the station.
EMBD: Embedded (e.g. CB hidden inside other cloud).
END: Runway end (stop end).
EST: Estimated.
ESTMD: Estimated.
FRMG: Forming.
FROIN: Frost on the instrument.
FROPA: Frontal passage.
FRQ: Frequent.
FT: Feet.
FZRANO: Freezing-rain sensor not available.
HAZARD: Hazard.
HGT: Height.
HILLS: Hills.
HR: Hour.
HVY: Heavy.
HZY: Hazy.
ICG: Icing.
INTMT: Intermittent.
ISOL: Isolated.
LAST: Last (e.g. last staffed observation).
LENT: Lenticular (lens-shaped wave cloud).
LGT: Light.
LOC: Locally.
LTG: Lightning. Suffixes: IC in-cloud, CC cloud-to-cloud, CG cloud-to-ground, CA cloud-to-air.
LWR: Lower.
MAX: Maximum.
MID: Runway mid-point.
MIN: Minimum.
MISG: Missing.
MOD: Moderate.
MOV: Moving.
MT: Mountain(s).
MTN: Mountain.
MTNS: Mountains.
NEXT: Next.
NXT: Next.
OBS: Observation.
OBSC: Obscured.
OBST: Obstacle(s).
OCNL: Occasional.
OHD: Overhead.
OVC: Overcast (8 oktas).
PAST: Past.
PCPN: Precipitation.
PNO: Precipitation-amount gauge (tipping bucket) not available.
PRES: Pressure.
PWINO: Present-weather sensor not available.
QUADS: Quadrants.
RAG: Ragged (cloud base).
RVRNO: Runway visual range should be reported but is missing.
RWY: Runway.
SCT: Scattered (3–4 oktas).
SFC: Surface.
SLPNO: Sea level pressure not available.
SOG: Snow on ground (depth in cm, Canada).
STFD: Staffed.
TDZ: Touchdown zone.
THR: Runway threshold.
TO: To / towards.
TPG: Topping (cloud covering hilltops).
TR: Trace (a small amount of that cloud type).
TSNO: Thunderstorm (lightning) sensor not available.
TWR: Control tower (e.g. TWR VIS = visibility observed from the tower).
VC: In the vicinity (5–10 sm / 8–16 km from the station).
VIRGA: Precipitation falling from cloud but evaporating before reaching the ground.
VIS: Visibility.
VISNO: Visibility at the secondary location not available.
VRY: Very.
WIND: Wind.
WND: Wind.
WSHFT: Wind shift.
WX: Weather.

Frequently asked questions

What is a TAF?

A TAF (Terminal Aerodrome Forecast) is the official weather forecast for an airport, usually valid for 9 to 30 hours. It uses the same codes as a METAR, plus change groups that show how conditions develop.

What is the difference between BECMG and TEMPO?

BECMG means conditions change gradually during the period and then stay that way. TEMPO means temporary fluctuations, each lasting less than an hour and together less than half of the period, after which the base conditions return.

What does PROB30 or PROB40 mean in a TAF?

PROB30 and PROB40 give a 30% or 40% probability that the conditions in that group occur. They can be combined with TEMPO, for example PROB40 TEMPO.

What does FM mean in a TAF?

FM (from) marks a rapid, complete change at the given time. Everything forecast before it is replaced by the new group.

More aviation weather tools

METAR decoderPaste any raw METAR, or pull one live from an airport, and get a plain-language breakdown of every group.Crosswind calculatorHeadwind, tailwind and crosswind components for any runway, with gusts and your own limit. Load the live wind and runways of an airport.Flight category checkerVFR, MVFR, IFR or LIFR from visibility and ceiling, with the thresholds explained and what sets the category.Unit converterhPa and inHg, km, NM and sm, knots, feet and flight levels, °C and °F, and fuel volume to weight.