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.