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METAR is a format for reporting weather information. A METAR weather report is predominantly used by aircraft pilots, and by meteorologists, who use aggregated METAR information to assist in weather forecasting.


Raw METAR is the most common format in the world for the transmission of observational weather data.[ citation needed ] It is highly standardized through the International Civil Aviation Organization (ICAO), which allows it to be understood throughout most of the world.

Report names

The United States Federal Aviation Administration (FAA) in its publication the Aeronautical Information Manual describes the report as aviation routine weather report [1] while the international authority for the code form, the World Meteorological Organization (WMO), describes it as the aerodrome routine meteorological report. The National Oceanic and Atmospheric Administration (part of the United States Department of Commerce) and the United Kingdom's Met Office both employ the definition used by the FAA. METAR is also known as Meteorological Terminal Aviation Routine Weather Report [2] or Meteorological Aerodrome Report. [3]


METARs typically come from airports or permanent weather observation stations. Reports are generated once an hour or half-hour at most stations, but if conditions change significantly at a staffed location, a report known as a special (SPECI) may be issued. Some stations make regular reports more frequently, such as Pierce County Airport (ICAO code: KPLU) which issues reports three times per hour. Some METARs are encoded by automated airport weather stations located at airports, military bases, and other sites. Some locations still use augmented observations, which are recorded by digital sensors, encoded via software, and then reviewed by certified weather observers or forecasters prior to being transmitted. Observations may also be taken by trained observers or forecasters who manually observe and encode their observations prior to transmission.[ citation needed ]


The METAR format was introduced 1 January 1968 internationally and has been modified a number of times since. North American countries continued to use a Surface Aviation Observation (SAO) for current weather conditions until 1 June 1996, when this report was replaced with an approved variant of the METAR agreed upon in a 1989 Geneva agreement. The WMO's publication No. 782 "Aerodrome Reports and Forecasts" contains the base METAR code as adopted by the WMO member countries. [4]

Information contained in a METAR

A typical METAR contains data for the temperature, dew point, wind direction and speed, precipitation, cloud cover and heights, visibility, and barometric pressure. A METAR may also contain information on precipitation amounts, lightning, and other information that would be of interest to pilots or meteorologists such as a pilot report or PIREP, colour states and runway visual range (RVR).

In addition, a short period forecast called a TREND may be added at the end of the METAR covering likely changes in weather conditions in the two hours following the observation. These are in the same format as a Terminal Aerodrome Forecast (TAF).

The complement to METARs, reporting forecast weather rather than current weather, are TAFs. METARs and TAFs are used in VOLMET broadcasts.


METAR code is regulated by the World Meteorological Organization in consort with the International Civil Aviation Organization. In the United States, the code is given authority (with some U.S. national differences from the WMO/ICAO model) under the Federal Meteorological Handbook No. 1 (FMH-1), which paved the way for the U.S. Air Force Manual 15-111 [5] on Surface Weather Observations, being the authoritative document for the U.S. Armed Forces. A very similar code form to the METAR is the SPECI. Both codes are defined at the technical regulation level in WMO Technical Regulation No. 49, Vol II, which is copied over to the WMO Manual No. 306 and to ICAO Annex III.

METAR conventions

Although the general format of METARs is a global standard, the specific fields used within that format vary somewhat between general international usage and usage within North America. Note that there may be minor differences between countries using the international codes as there are between those using the North American conventions. The two examples which follow illustrate the primary differences between the two METAR variations. [6] [7]

Example METAR codes

International METAR codes

The following is an example METAR from Burgas Airport in Burgas, Bulgaria. It was taken on 4 February 2005 at 16:00 Coordinated Universal Time (UTC).

METAR LBBG 041600Z 12012MPS 090V150 1400 R04/P1500N R22/P1500U +SN BKN022 OVC050 M04/M07 Q1020 NOSIG 8849//91=

North American METAR codes

North American METARs deviate from the WMO (who write the code on behalf of ICAO) FM 15-XII code. Details are listed in the FAA's Aeronautical Information Manual (AIM), but the non-compliant elements are mostly based on the use of non-standard units of measurement. This METAR example is from Trenton-Mercer Airport near Trenton, New Jersey, and was taken on 5 December 2003 at 18:53 UTC.

METAR KTTN 051853Z 04011KT 1/2SM VCTS SN FZFG BKN003 OVC010 M02/M02 A3006 RMK AO2 TSB40 SLP176 P0002 T10171017= [9]

Note that what follows are not part of standard observations outside of the United States and can vary significantly.

In Canada, RMK is followed by a description of the cloud layers and opacities, in eighths (oktas). For example, CU5 would indicate a cumulus layer with 58 opacity. [11]

Cloud reporting

Cloud coverage is reported by the number of 'oktas' (eighths) of the sky that is occupied by cloud.

This is reported as: [12]

SKC"No cloud/Sky clear" used worldwide but in North America is used to indicate a human generated report [13] [14]
NCD"Nil Cloud detected" automated METAR station has not detected any cloud, either due to a lack of it, or due to an error in the sensors
CLR"No clouds below 12,000 ft (3,700 m) (U.S.) or 25,000 ft (7,600 m) (Canada)", used mainly within North America and indicates a station that is at least partly automated [13] [14]
NSC"No (nil) significant cloud", i.e., none below 5,000 ft (1,500 m) and no TCU or CB. Not used in North America.
FEW"Few" = 1–2 oktas
SCT"Scattered" = 3–4 oktas
BKN"Broken" = 5–7 oktas
OVC"Overcast" = 8 oktas, i.e., full cloud coverage
TCU Towering cumulus cloud, e.g., SCT016TCU
CB Cumulonimbus cloud, e.g., FEW015CB
VV"Vertical Visibility" = Clouds cannot be seen because of fog or heavy precipitation, so vertical visibility is given instead.

Flight categories in the U.S.

METARs can be expressed concisely using so-called aviation flight categories, which indicates what classes of flight can operate at each airport by referring to the visibility and ceiling in each METAR. Four categories are used in the U.S.: [15]

VFR > 5 miand > 3000 ft AGL
Marginal VFRBetween 3 and 5 miand/or Between 1,000 and 3,000 ft AGL
IFR 1 mi or more but less than 3 miand/or 500 ft or more but less than 1,000 ft
Low IFR< 1 miand/or < 500 ft

METAR weather codes

METAR abbreviations used in the weather and events section. Remarks section will also include began and end times of the weather events. [16] Codes before remarks will be listed as "-RA" for "light rain". Codes listed after remarks may be listed as "RAB15E25" for "Rain began at 15 minutes after the top of the last hour and ended at 25 minutes after the top of the last hour."

Combinations of two precipitation types are accepted; e.g., RASN (Rain and snow mixed), SHGSSN etc.

Intensity-Light intensity
Intensity(blank)Moderate intensity
Intensity+Heavy intensity
DescriptorVCIn the vicinity (5-10 mi / 8-16 km from station); visible phenomena:


DescriptorRERecent hour's most important past phenomenon with residues:

TS, RA, FZRA, SN, BLSN, GR, GS, PL (e.g.:METAR ... Q1010 RERA=)

DescriptorMIShallow [French: Mince] (fog descriptor)
DescriptorPRPartial (fog descriptor)
DescriptorBCPatches [French: Bancs] (fog descriptor)
DescriptorDRLow drifting below eye level; including: DRSN, DRSA, DRDU
DescriptorBLBlowing at or above eye level; including: BLSN, BLSA, BLDU
Descriptor*SH Showers (*also without precipitation: VCSH)
Descriptor*TS Thunderstorm (*also without precipitation: VCTS, RETS or as Thunder)
DescriptorFZFreezing; including: FZDZ, FZRA, FZFG
PrecipitationDZ Drizzle
PrecipitationRA Rain
PrecipitationSN Snow (snowflakes)
PrecipitationSG Snow Grains
PrecipitationGS Graupel [French: Grésil], Snow Pellets and/or Small Hail (not in the US) [note 2] [17] Elsewhere hail is GR when it is 5 mm or greater [18] Outside of the US when the hail is less than 5 mm the code GS is used. [18] )
PrecipitationGR Hail [French: Grêle] (in the US includes Small Hail) [note 2]
PrecipitationPL Ice Pellets
PrecipitationIC Ice Crystals
PrecipitationUPUnknown Precipitation
ObscurationFG Fog (visibility less than 1 km)
ObscurationBR Mist [French: Brume] (due to water droplets, visibility between 1 and 5 km)
ObscurationHZ Haze (due to dry particulates, visibility between 1 and 5 km)
ObscurationVAVolcanic Ash
ObscurationDUWidespread Dust
ObscurationFUSmoke [French: Fumée]
OtherSQ Squall
OtherPODust [French: Poussière] or Sand Whirls
OtherDS Duststorm
OtherSS Sandstorm
OtherFC Funnel Cloud
TimeBBegan At Time
TimeEEnded At Time
Time2 digitsMinutes of current hour
Time4 digitsHour/Minutes Zulu Time

U.S. METAR abbreviations

The following METAR abbreviations are used in the United States; some are used worldwide: [6]

METAR and TAF Abbreviations and Acronyms:

$maintenance check indicator/indicator that visual range data follows; separator between temperature and dew point data.
ACC altocumulus castellanus ACFT MSHPaircraft mishap
ACSLaltocumulus standing lenticular cloud ALPairport location point
ALQDSall quadrants (official)ALQSall quadrants (unofficial)
AO1automated station without precipitation discriminatorAO2automated station with precipitation discriminator
APRXapproximatelyATCTairport traffic control tower
AUTOfully automated reportCcenter (with reference to runway designation)
CAcloud-air lightning CB cumulonimbus cloud
CBMAMcumulonimbus mammatus cloud CCcloud-cloud lightning
CCSL cirrocumulus standing lenticular cloud cd candela
CGcloud-ground lightningCHIcloud-height indicator
CHINOsky condition at secondary location not availableCIGceiling
CONScontinuousCORcorrection to a previously disseminated observation
DOC Department of Commerce DOD Department of Defense
DOT Department of Transportation DSIPTGdissipating
DSNTdistantDVRdispatch visual range
Eeast, ended, estimated ceiling (SAO)FAA Federal Aviation Administration
FIBIfiled but impracticable to transmitFIRSTfirst observation after a break in coverage at manual station
FMH-1Federal Meteorological Handbook No.1, Surface Weather Observations & Reports (METAR)FMH2Federal Meteorological Handbook No.2, Surface Synoptic Codes
FROPA frontal passageFROINfrost on the indicator
FRQfrequentFT feet
FZRANOfreezing rain sensor not availableGgust
HLSTOhailstoneICAO International Civil Aviation Organization
KT knots Lleft (with reference to runway designation)
LASTlast observation before a break in coverage at a manual stationLSTlocal standard time
LTG lightning LWRlower
Mminus, less thanMAXmaximum
METARroutine weather report provided at fixed intervalsMINminimum
MOVmoved/moving/movementMT mountains
NnorthN/Anot applicable
NCDC National Climatic Data Center NEnortheast
NOS National Ocean Service NOSPECIno SPECI reports are taken at the station
NOTAM Notice to Airmen NWnorthwest
NWS National Weather Service OCNLoccasional
OFCMOffice of the Federal Coordinator for MeteorologyOHDoverhead
OVRoverPindicates greater than the highest reportable value
PCPN precipitation PK WNDpeak wind
PNOprecipitation amount not availablePRES pressure
PRESFR pressure falling rapidlyPRESRR pressure rising rapidly
PWINOprecipitation identifier sensor not availableRright (with reference to runway designation), runway
RTDRoutine Delayed (late) observationRVreportable value
RVR Runway visual range RVRNO RVR system values not available
RWY runway Ssouth
SCSL stratocumulus standing lenticular cloud SEsoutheast
SFCsurface, i.e., ground level)SLP sea-level pressure
SLPNO sea-level pressure not availableSM statute miles
SNINCRsnow increasing rapidlySOGsnow on the ground
SPECIan unscheduled report taken when certain criteria have been metSTNstation
SWsouthwestTCU towering cumulus
TS thunderstorm TSNO thunderstorm information not available
TWR tower UNKNunknown
UTC Coordinated Universal Time Vvariable
VIS visibility VISNOvisibility at secondary location not available
VRvisual rangeVRBvariable
WwestWG/SOWorking Group for Surface Observations
WMO World Meteorological Organization WND wind
WS wind shear WSHFTwind shift
ZZulu, i.e., Coordinated Universal Time

U.S. METAR numeric codes

Additional METAR numeric codes listed after RMK. [16]

112346 hour maximum temperature. Follows RMK with five digits starting with 1. Second digit is 0 for positive and 1 for negative. The last 3 digits equal the temperature in tenths.

This example value equals −23.4 °C (−10 °F).

201236 hour minimum temperature. Follows RMK with five digits starting with 2. Second digit is 0 for positive and 1 for negative. The last 3 digits equal the temperature in tenths.

This example value equals 12.3 °C (54 °F).

4/012Total snow depth in inches. Follows RMK starting with 4/ and followed by 3 digit number that equals snow depth in inches.

This example value equals 12 inches of snow currently on the ground.

40234012324-hour maximum and minimum temperature. Follows RMK with nine digits starting with 4. The second and sixth digit equals 0 for positive for 1 for negative. Digits 3–5 equal the maximum temperature in tenths and the digits 7–9 equals the minimum temperature in tenths.

This example value equals 23.4 °C (74 °F) and 12.3 °C (54 °F).

520063 hour pressure tendency. Follows RMK with 5 digits starting with 5. The second digit gives the tendency. In general 0–3 is rising, 4 is steady and 5–8 is falling. The last 3 digits give the pressure change in tenths of a millibar in the last 3 hours.

This example indicates a rising tendency of 0.6 millibars (0.018 inHg). [19]

601233 or 6 hour precipitation amount. Follows RMK with 5 digits starting with 6. The last 4 digits are the inches of rain in hundredths. If used for the observation nearest to 00:00, 06:00, 12:00, or 18:00 UTC, it represents a 6-hour precipitation amount. If used in the observation nearest to 03:00, 09:00, 15:00 or 21:00 UTC, it represents a 3-hour precipitation amount.

This example shows 1.23 inches (31 mm) of rain.

7024624-hour precipitation amount. Follows RMK with 5 digits starting with 7. The last 4 digits are the inches of rain in hundredths.

This example shows 2.46 inches (62 mm) of rain.

8/765Cloud cover using WMO code. Follows RMK starting with 8/ followed by a 3 digit number representing WMO cloud codes.
98060Duration of sunshine in minutes. Follows RMK with 5 digits starting with 98. The last 3 digits are the total minutes of sunshine.

This example indicates 60 minutes of sunshine.

931222Snowfall in the last 6-hours. Follows RMK with 6 digits starting with 931. The last 3 digits are the total snowfall in inches and tenths.

This example indicates 22.2 inches (560 mm) of snowfall.

933021Liquid water equivalent of the snow (SWE). Follows RMK with 6 digits starting with 933. The last 3 digits are the total inches in tenths.

This example indicates 2.1 inches (53 mm) SWE.

WMO codes for cloud types

The following codes identify the cloud types used in the 8/nnn part. [16]

CodeLow CloudsMiddle CloudsHigh Clouds
1 Cumulus
(fair weather)
2 Cumulus
3 Cumulonimbus
(no anvil)
(often with Cumulonimbus)
4 Stratocumulus
(from Cumulus)
5 Stratocumulus
(not Cumulus)
Cirrus / Cirrostratus
(low in sky)
6 Stratus or Fractostratus
(from Cumulus)
Cirrus / Cirrostratus
(hi in sky)
7 Fractocumulus / Fractostratus
(bad weather)
(with Altocumulus,
Altostratus, Nimbostratus)
(entire sky)
8 Cumulus and Stratocumulus Altocumulus
(with turrets)
9 Cumulonimbus
Cirrocumulus or
Cirrocumulus / Cirrus / Cirrostratus
/not validabove overcastabove overcast

See also


  1. Precipitation discriminators are electrically heated at sub-freezing temperatures to calculate the water equivalent of frozen precipitation and snow accumulation.
  2. 1 2 In the US Small Hail is included with regular hail and the Remarks section is used saying "GR LESS THAN 1/4".

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  1. "Chapter 7". Aeronautical Information Manual. Archived from the original on 2009-09-05. Retrieved 2007-12-01.
  2. METAR (MEteorological Terminal Aviation Routine Weather Report) Station Network at the Centre for Environmental Data Archival
  3. Aerodrome Meteorological Observation and Forecast Study Group (AMOFSG) at ICAO
  4. "782 – Aerodrome reports and forecasts: A user's handbook to the codes". World Meteorological Organization. Retrieved 2009-09-23.
  5. "Air Force Manual 15-111" (PDF). Archived from the original (PDF) on May 27, 2011.
  6. 1 2 METAR/TAF List of Abbreviations and Acronyms.
  7. "Pilot's Handbook of Aeronautical Knowledge" (PDF).
  8. Get Met 2012 Archived 2012-05-18 at the Wayback Machine published by the UK Met Office, p 13
  9. Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR)
  10. Key to METAR Surface Weather Observations
  11. Environment Canada (2012). "MMmetar.html". Retrieved March 28, 2012.
  12. "Aerodrome Weather Report – World Meteorological Organization" (PDF). Archived from the original (PDF) on February 24, 2012.
  13. 1 2 Sky Condition Group NsNsNshshshs or VVhshshs or SKC Department of Atmospheric Sciences at Texas A&M University
  14. 1 2 "MET – 3.0 Appendices". Archived from the original on October 31, 2011.
  15. "Aeronautical Information Manual, Section 7-1-7, 'Categorical Outlooks'". Federal Aviation Administration. Archived from the original on 2012-07-26.
  16. 1 2 3 "METAR/TAF List of Abbreviations and Acronyms" (PDF).
  17. "METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR)" (PDF).
  18. 1 2 10.2 Section II - hourly observations "UTC". See 10.2.10 Column 32 - weather and obstructions to vision
  19. "METAR HELP".
Format specifications
Software libraries
Current reports