View source for METAR

{{Short description|Format for weather reports used in aviation}}
{{For-multi|the village in Iran|Metar, Iran|the Israeli town|Meitar}}
[[File:METAR processing machine at KBTP.jpg|thumb|upright|A METAR processing and transmitting unit installed at [[Pittsburgh-Butler Regional Airport]], United States]]
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'''METAR'''<!--Don't add "METeorological Actual Report" or any other meaning here. See the "Report names" section below."--> is a format for reporting [[weather]] information. A METAR weather report is predominantly used by [[aircraft pilot]]s, and by [[meteorologist]]s, who use aggregated METAR information to assist in [[weather forecasting]].

Raw METAR is highly standardized through the [[International Civil Aviation Organization]] (ICAO), which enables it to be understood throughout most of the world.

==Report names==
In its publication the ''[[Aeronautical Information Manual]]'' (''AIM''), the United States [[Federal Aviation Administration]] (FAA)  describes the report as ''aviation routine weather report'',<ref name="AIM Chap7 Sec1">{{cite web |title=Chapter 7. Safety of Flight. Section 1. Meteorology |url=https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap7_section_1.html |publisher=[[Federal Aviation Administration]] |work=[[Aeronautical Information Manual]] |access-date=2024-12-27 |url-status=live |archive-url=https://web.archive.org/web/20090905114733/http://www.faa.gov/air_traffic/publications/ATpubs/AIM/Chap7/aim0701.html |archive-date=2009-09-05}}</ref> 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''<ref>[http://catalogue.ceda.ac.uk/uuid/50418e43c3c741618c34e75c22ef43e3 METAR (MEteorological Terminal Aviation Routine Weather Report) Station Network] at the Centre for Environmental Data Archival</ref> or ''Meteorological Aerodrome Report''.<ref>[http://www.icao.int/safety/meteorology/amofsg/AMOFSG%20Meeting%20Material/SN%2021%20Binder1.pdf Aerodrome Meteorological Observation and Forecast Study Group (AMOFSG)] at ICAO.</ref>

== Frequencies and types ==
{{Anchor|SPECI}}
METARs typically come from [[airport]]s or other permanent [[Weather station|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.<ref name="AWH">{{Cite AWH|year=2024|chapter=24}}</ref>{{rp|2}}{{efn|Criteria for issuing a SPECI includes beginning or ending of hazardous weather, aircraft mishap, decreasing visibility or ceiling, or any other condition deemed critical by the observer of the responsible agency.<ref name="AIM Chap7 Sec1" />|group=note}} Some stations make regular reports more frequently, such as [[Pierce County Airport]] (ICAO code: KPLU) which issues reports three times per hour.<ref>{{cite web |title=Pierce County-Thun Field |url=https://www.weather.gov/wrh/timeseries?site=KPLU |website=National Weather Service |publisher=[[NOAA]] |access-date=27 December 2024 |language=EN-US}}</ref> In addition to METARs and SPECIs, ASOS One-Minute Observations (OMO) are updated once a minute. OMOs can be in various formats, including the METAR format.<ref name="AWH" />{{rp|3}}

Some METARs are encoded by [[automated airport weather station]]s 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. In the United States, prior to mid-1990s, most observations are made manually, but today the vast majority are automated or augmented observations.<ref name="AWH" />{{rp|2}}

==History==
The METAR format was introduced internationally on 1 January 1968, and has been modified a number of times since. [[North America]]n 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.<ref>{{cite web |url=http://www.wmo.int/e-catalog/detail_en.php?PUB_ID=70&SORT=N&q=Aerodrome%20Reports%20and%20Forecasts |title=782 – Aerodrome reports and forecasts: A user's handbook to the codes |access-date=2009-09-23 |work=World Meteorological Organization}}</ref>

==Information contained in a METAR==
A typical METAR contains data for the airport identifier, time of observation, [[wind]] direction and speed, [[visibility]], current weather phenomena such as [[precipitation (meteorology)|precipitation]], [[cloud]] cover and heights, [[temperature]], [[dew point]], and [[Atmospheric pressure|barometric pressure]]. This information forms the body of the report, consisting a maximum of 11 groups of information.<ref name="AWH" />{{rp|5}} 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 state]]s and [[runway visual range]] (RVR). These may be provided in coded or plain language and appended to the end of the METAR as remarks.<ref name="AWH" />{{rp|6}}

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.

=== Cloud reporting ===
[[Cloud cover]]age is reported by the number of "[[okta]]s" (eighths) of the sky that is occupied by cloud. Automated substation substitutes time averaging of sensor data gathered during 30-minute period prior to reporting.<ref name="AWH" />{{rp|2,4}}

This is reported as:<ref>{{Cite web|url=http://www.dmi.dk/dmi/koder.pdf|archive-url=https://web.archive.org/web/20120224010553/http://www.dmi.dk/dmi/koder.pdf|url-status=dead|title=Aerodrome Weather Report – World Meteorological Organization|archive-date=2012-02-24}}</ref>

{| class="wikitable"
|+  Cloud coverage codes
!scope="col"| Abbreviation
!scope="col"| Meaning
|-
!scope="row"| SKC
| "No cloud/Sky clear" used worldwide but in North America is used to indicate a human generated report<ref name="amuni">[http://atmo.tamu.edu/class/METAR/metar-pg10-sky.html Sky Condition Group NsNsNshshshs or VVhshshs or SKC] Department of Atmospheric Sciences at Texas A&M University</ref><ref name="trancan">{{Cite web|url=http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-met-3-0-2589.htm|archive-url=https://web.archive.org/web/20111031083839/http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-met-3-0-2589.htm|url-status=dead|title=MET – 3.0 Appendices|archive-date=October 31, 2011}}</ref>
|-
!scope="row"| 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
|-
!scope="row"| CLR
| "No clouds below {{convert|12000|ft|abbr=on}} (US) or {{convert|25000|ft|abbr=on}} (Canada)", used mainly within North America and indicates a station that is at least partly automated<ref name="amuni"/><ref name="trancan"/>
|-
!scope="row"| NSC
| "No (nil) significant cloud", ''i.e.'', none below {{convert|5000|ft|abbr=on}} and no [[towering cumulus|TCU]] or [[cumulonimbus cloud|CB]]. Not used in North America.
|-
!scope="row"| FEW
| "Few" = 1–2 oktas
|-
!scope="row"| SCT
| "Scattered" = 3–4 oktas
|-
!scope="row"| BKN
| "Broken" = 5–7 oktas
|-
!scope="row"| OVC
| "[[Overcast]]" = 8 oktas, ''i.e.'', full cloud coverage
|-
!scope="row"| TCU
| [[Cumulus congestus cloud|Towering cumulus cloud]], ''e.g.'', SCT016TCU
|-
!scope="row"| CB
| [[Cumulonimbus cloud]], ''e.g.'', FEW015CB
|-
!scope="row"| VV
| "Vertical visibility" = clouds cannot be seen because of fog or heavy precipitation, so vertical visibility is given instead.
|}

The following codes identify the [[List of cloud types|cloud types]] used in the 8/nnn part of RMK.<ref name="NWS-METAR+TAF List" />

{| class="wikitable"
|+ WMO codes for cloud types
|-
!scope="col"| Code
!scope="col"| Low clouds
!scope="col"| Middle clouds
!scope="col"| High clouds
|-
!scope="row"| 0
|none||none||none
|-
!scope="row"| 1
| [[Cumulus]]<br />(fair weather)
| [[Altostratus]]<br />(thin)
| [[Cirrus cloud|Cirrus]]<br />(filaments)
|-
!scope="row"| 2
| [[Cumulus]]<br />(towering)
| [[Altostratus]]<br />(thick)
| [[Cirrus cloud|Cirrus]]<br />(dense)
|-
!scope="row"| 3
| [[Cumulonimbus]]<br />(no anvil)
| [[Altocumulus]]<br />(thin)
| [[Cirrus cloud|Cirrus]]<br />(often with [[cumulonimbus]])
|-
!scope="row"| 4
| [[Stratocumulus]]<br />(from [[cumulus]])
| [[Altocumulus]]<br />(patchy)
| [[Cirrus cloud|Cirrus]]<br />(thickening)
|-
!scope="row"| 5
| [[Stratocumulus]]<br />(not [[cumulus]])
| [[Altocumulus]]<br />(thickening)
| [[Cirrus cloud|Cirrus]] / [[cirrostratus]]<br />(low in sky)
|-
!scope="row"| 6
| [[Stratus cloud|Stratus]] or [[Fractostratus]]<br />(fair)
| [[Altocumulus]]<br />(from [[cumulus]])
| [[Cirrus cloud|Cirrus]] / [[cirrostratus]]<br />(hi in sky)
|-
!scope="row"| 7
| [[Fractocumulus]] / [[fractostratus]]<br />(bad weather)
| [[Altocumulus]]<br />(with [[altocumulus]],<br />[[altostratus]], [[nimbostratus]])
| [[Cirrostratus]]<br />(entire sky)
|-
!scope="row"| 8
| [[Cumulus]] and [[stratocumulus]]
| [[Altocumulus]]<br />(with turrets)
| [[Cirrostratus]]<br />(partial)
|-
!scope="row"| 9
| [[Cumulonimbus]]<br />(thunderstorm)
| [[Altocumulus]]<br />(chaotic)
| [[Cirrocumulus]] or<br />[[Cirrocumulus]] / [[Cirrus cloud|cirrus]] / [[cirrostratus]]
|-
!scope="row"| /
| not valid
| above overcast
| above overcast
|}

=== Wind reporting ===
Wind observation measures the horizontal vector component of the wind, which includes both direction and speed. These are determined by evaluating the measurement over a 2-minute period.<ref name="AWH" />{{rp|24-10}}

The wind direction is coded with the first three digits in tens of degrees relative to the [[true north]]. If wind speed is less than or equal to {{cvt|6|kn}}, the wind direction will be displayed as variable or "VRB". If the wind speed is greater than 6 knots, but the direction varies more than 60° in the past 2 minutes, METAR will report the range of wind direction. For example, <code>21010KT 180V240</code> suggests the wind was variable from 180° to 240° at 10 knots.<ref name="AWH" />{{rp|10}}

Immediately after the wind direction is the wind speed, coded in two or three digits measured in knots, km/h or m/s. If during past 10 minutes, the weather station detects more than {{cvt|10|kn}} between minimum and maximum windspeed, METAR determines a [[wind gust]] exists and reports the maximum instantaneous windspeed.<ref name="AWH" />{{rp|10}}

If the air is motionless, the wind will be reported as calm and coded as <code>00000KT</code>.<ref name="AWH" />{{rp|10}}

=== Visibility and runway visual range ===
Visibility measures the atmospheric opacity. It is the greatest distance where at least half of the horizon circle can be seen from the surface.<ref name="AWH" />{{rp|11}}

[[Runway visual range]] (RVR) is an instrument-derived measurement that suggests the horizontal distance an observer may see down the runway. In the US, for stations with RVR reporting capacity, this information is omitted from the METAR unless the visibility is at or below {{cvt|1|mi}}, or the designated instrument runway's RVR is at or below {{cvt|6000|ft}}. RVR of up to four designated runways may be reported, depending on the country.<ref name="AWH" />{{rp|11}}

== Regulations and conventions ==
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 US national differences from the WMO/ICAO model) under the ''Federal Meteorological Handbook No. 1'' (FMH-1), which paved the way for the [[United States Air Force|US Air Force]] Manual 15-111<ref>{{Cite web|url=http://www.e-publishing.af.mil/shared/media/epubs/AFMAN15-111.pdf|archive-url=https://web.archive.org/web/20110527003108/http://www.e-publishing.af.mil/shared/media/epubs/AFMAN15-111.pdf|url-status=dead|title=Air Force Manual 15-111|archive-date=May 27, 2011}}</ref> on Surface Weather Observations, being the authoritative document for the US 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.

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 — ICAO allows member countries to modify METAR code for use in their particular countries, as long as ICAO is notified.<ref name="AWH" />{{rp|5}}

== Examples ==

The two examples which follow illustrate the primary differences between the international and the North American METAR variations.<ref name="NWS-METAR+TAF List" /><ref>{{Cite PHAK}}</ref>{{page needed|date=December 2024}}

===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='''

*'''METAR''' indicates that the following is a standard hourly observation.
*'''LBBG''' is the [[International Civil Aviation Organization airport code|ICAO airport code]] for [[Burgas Airport]].
*'''041600Z''' indicates the time of the observation. It is the day of the month (04) followed by the time of day (1600 [[Zulu time]], which equals 4:00&nbsp;pm [[Greenwich Mean Time]] or 6:00&nbsp;pm local time).
*'''12012MPS''' indicates the [[wind direction]] is from 120° ([[Boxing the compass|east-southeast]]) at a speed of {{convert|12|m/s|kn mph km/h|abbr=on|lk=in}}. Speed measurements can be in knots (abbreviated KT) or metres per second (abbreviated MPS).
*'''090V150''' indicates the wind direction is varying from 90° true (east) to 150° true (south-southeast).
*'''1400''' indicates the [[prevailing visibility]] is {{convert|1400|m|abbr=on}}.
*'''R04/P1500N''' indicates the Runway Visual Range (RVR) along [[runway]] 04 is {{convert|1500|m|abbr=on}} and not changing significantly.
*'''R22/P1500U''' indicates RVR along runway 22 is {{convert|1500|m|abbr=on}} and rising.
*'''+SN''' indicates [[snow]] is falling at a heavy intensity. If any precipitation begins with a minus or plus (-/+), it's either light or heavy.
*'''BKN022''' indicates a broken (over half the sky) cloud layer with its base at {{convert|2200|ft|abbr=on}} [[above ground level]] (AGL). The lowest "BKN" or "OVC" layer specifies the [[ceiling (cloud)|cloud ceiling]].
*'''OVC050''' indicates an unbroken cloud layer (overcast) with its base at {{convert|5000|ft|abbr=on}} above ground level (AGL). 
*'''M04/M07''' indicates the temperature is {{convert|-4|C|0}} and the [[dew point]] is {{convert|-7|C|0}}. An M in front of the number indicates that the temperature/dew point is [[Melting point|below zero]] Celsius.
*'''Q1020''' indicates the current [[altimeter setting]] (in [[QNH]]) is {{convert|1020|hPa|inHg|lk=on|abbr=on|2}}.
*'''NOSIG''' is an example of a [[Trend type forecast|TREND]] forecast which is appended to METARs at stations while a forecaster is on watch. NOSIG means that no significant change is expected to the reported conditions within the next 2 hours.
*'''8849//91''' indicates the condition of the runway.
** The first two characters indicate which runway is being described.
*** If there are two or more runways with the same number, some locations will use three characters (e.g. '''25L''' and '''25R'''). Otherwise, the left runway will use just its number and the right runway will add 50 (e.g. '''25''' = 25L and '''75''' = 25R).
*** '''88''' indicates all the airport's runways.
*** '''99''' indicates repetition of the last message as no new information received.
** '''4''' means the runway is coated with dry snow
** '''9''' means 51% to 100% of the runway is covered
** '''//''' means the thickness of the coating was either not measurable or not affecting usage of the runway
** '''91''' means the braking index is bad, in other words the tires have bad grip on the runway
*'''CAVOK''' is an abbreviation for '''''C'''eiling '''A'''nd '''V'''isibility '''OK''''', indicating no cloud below {{convert|5000|ft|abbr=on}} or the highest minimum sector altitude and no [[Cumulonimbus cloud|cumulonimbus]] or [[Towering cumulus cloud|towering cumulus]] at any level, a visibility of {{convert|10|km|abbr=on|0}} or more and no significant weather change.<ref>[http://www.metoffice.gov.uk/media/pdf/4/1/Get_Met_2012_amends_tag_Artwork.pdf Get Met 2012] {{webarchive|url=https://web.archive.org/web/20120518165852/http://www.metoffice.gov.uk/media/pdf/4/1/Get_Met_2012_amends_tag_Artwork.pdf |date=2012-05-18}} published by the UK Met Office, p 13</ref>
*'''=''' indicates the end of the METAR

===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|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='''<ref>[http://www.nws.noaa.gov/oso/oso1/oso12/document/guide.shtml Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR)]</ref>

*'''METAR''' indicates that the following is a standard hourly observation.
*'''KTTN''' is the ICAO identifier for the [[Trenton-Mercer Airport]].
*'''051853Z''' indicates the day of the month is the 5th and the time of day is 1853 Zulu/[[UTC]], or 1:53PM [[Eastern Time Zone|Eastern Standard Time]].
*'''04011KT''' indicates the wind is from 040° true (north east) at {{convert|11|kn|km/h mph}}. In the United States, the wind direction must have a 60° or greater variance for variable wind direction to be reported and the wind speed must be greater than {{convert|3|kn|km/h mph}}.
*'''1/2SM''' indicates the prevailing visibility is {{convert|1/2|mi|m|abbr=on}} SM = statute [[mile]].
*'''VCTS''' indicates a [[thunderstorm]] (TS) in the vicinity (VC), which means from {{convert|5|-|10|mi|abbr=on|0}}.
*'''SN''' indicates snow is falling at a moderate intensity; a preceding plus or minus sign (+/-) indicates heavy or light precipitation. Without a +/- sign, moderate precipitation is assumed.
*'''FZFG''' indicates the presence of freezing [[fog]].
*'''BKN003 OVC010''' indicates a broken ({{frac|5|8}} to {{frac|7|8}} of the sky covered) cloud layer at {{convert|300|ft|abbr=on}} [[above ground level]] (AGL) and an overcast (8/8 of the sky covered) layer at {{convert|1000|ft|abbr=on}}.
*'''M02/M02''' indicates the temperature is {{convert|-2|C|0}} and the dew point is {{convert|-2|C|0}}. An M in front of the number indicates a negative Celsius temperature/dew point ("minus").
*'''A3006''' indicates the altimeter setting is {{convert|30.06|inHg|hPa|abbr=on}}.
*'''RMK''' indicates the remarks section follows.

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

*'''AO2''' indicates that the station is automated with a precipitation discriminator (rain/snow) sensor.<ref group="note">Precipitation discriminators are electrically heated at sub-freezing temperatures to calculate the water equivalent of frozen precipitation and snow accumulation.</ref> Stations that aren't equipped with a rain/snow sensor are designated '''AO1'''.<ref>[http://www.ncdc.noaa.gov/oa/climate/conversion/swometardecoder.html Key to METAR Surface Weather Observations]</ref>
*'''TSB40''' indicates the thunderstorm began at 40 minutes past the hour at 1840 Zulu/[[UTC]], or 1:40&nbsp;p.m. [[Eastern Standard Time (North America)|Eastern Standard Time]].
*'''SLP176''' indicates the current barometric pressure extrapolated to sea level is {{convert|1017.6|hPa|inHg|abbr=on}}.
*'''P0002''' indicates that {{convert|0.02|in|1}} of [[liquid]]-equivalent precipitation accumulated during the last hour.
*'''T10171017''' is a breakdown of the temperature and dew point in eight digits separated into two groups of four. The first four digits (1017) indicate the temperature. The first digit (1) designates above or below zero Celsius (0=above zero 1=below zero). The next three digits in the group "017" give the temperature in degrees and tenths of a degree Celsius, {{convert|-1.7|C}}. The last four digits "1017" indicate the dew point, {{convert|-1.7|C}}. Note: ASOS software, as of this update, uses whole degrees in °F to compute the °C values in this group.{{Citation needed|date=December 2011}}
*'''=''' indicates the end of the METAR.
In Canada, '''RMK''' is followed by a description of the cloud layers and opacities, in eighths ([[okta]]s). For example, CU5 would indicate a cumulus layer with {{frac|5|8}} opacity.<ref>{{cite web |url= http://meteocentre.com/doc/metar.html |title=METAR Study Guide |work=MétéoCentre.com |access-date=28 March 2012}}</ref>

==Flight categories in the US ==
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 US:<ref>{{cite web|url=http://www.faa.gov/air_traffic/publications/ATpubs/AIM/aim0701.html |title=Aeronautical Information Manual, Section 7-1-7, 'Categorical Outlooks'. |publisher=[[Federal Aviation Administration]] |url-status=dead |archive-url=https://web.archive.org/web/20120726013603/http://www.faa.gov/air_traffic/publications/atpubs/aim/aim0701.html |archive-date=2012-07-26}}</ref>

{| class="wikitable"
|+ METARS expressed as US flight categories
!scope="col"| Category
!scope="col"| Visibility
!scope="col"| Ceiling
|-
!scope="row"| [[Visual flight rules|VFR]]
| > 5&nbsp;mi
| and > 3000&nbsp;ft AGL
|-
!scope="row"| Marginal VFR
| Between 3 and 5&nbsp;mi
| and/or between 1,000 and 3,000&nbsp;ft AGL
|-
!scope="row"| [[Instrument flight rules|IFR]]
| 1&nbsp;mi or more but less than 3&nbsp;mi
| and/or 500&nbsp;ft or more but less than 1,000&nbsp;ft
|-
!scope="row"| Low IFR
| < 1&nbsp;mi
|  and/or < 500&nbsp;ft
|}

== METAR weather codes ==

METAR abbreviations used in the weather and events section. Remarks section will also include begin and end times of the weather events.<ref name="NWS-METAR+TAF List">{{Cite web|url=https://www.weather.gov/media/wrh/mesowest/metar_decode_key.pdf|title=METAR/TAF List of Abbreviations and Acronyms |website=National Weather Service}}</ref> 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''. If more than one type of weather is present, METAR will report in the following order:<ref name="AWH" />{{rp|13}}
# Tornadic activity
# Thunderstorm
# Most dominating weather
# Precipitation
# Obscuration

{| class="wikitable"
|+ 
!scope="col"| Type
!scope="col"| {{abbr|Abbr.|Abbreviations}}
!scope="col"| Meaning
|-
!scope="row"| Intensity 
| - 
| Light intensity
|-
!scope="row"| Intensity 
| (blank) 
| Moderate intensity
|-
!scope="row"| Intensity 
| + 
| Heavy intensity
|-
!scope="row"| Descriptor 
| VC 
| In the vicinity (5–10 [[Mile|mi]] / 8–16 [[Kilometre|km]] from [[Weather station|station]]); visible phenomena:<br>
TS, SH, FG, DS, SS, VA, PO, FC, BLSN, BLDU, BLSA 
|-
!scope="row"| Descriptor 
| RE 
| Recent hour's most important past phenomenon with residues: <br>
TS, RA, FZRA, SN, BLSN, GR, GS, PL (''e.g.:'' <small>METAR ... Q1010 RERA=</small>)
|-
!scope="row"| Descriptor 
| MI 
| Shallow {{small|[{{Langx|fr|Mince|link=no}}]}} (fog descriptor)
|-
!scope="row"| Descriptor 
| PR 
| Partial (fog descriptor)
|-
!scope="row"| Descriptor 
| BC 
| Patches {{small|[{{Langx|fr|Bancs|link=no}}]}} (fog descriptor)
|-
!scope="row"| Descriptor 
| DR 
| Low drifting below eye level; including: [[Blowing snow|DRSN]], DRSA, DRDU 
|-
!scope="row"| Descriptor 
| BL 
| Blowing at or above eye level; including: [[Blowing snow|BLSN]], BLSA, BLDU 
|-
!scope="row"| Descriptor* 
| SH 
| [[Shower (precipitation)|Showers]] (*also without precipitation: VCSH)
|-
!scope="row"| Descriptor* 
| TS 
| [[Thunderstorm]] (*also without precipitation: VCTS, RETS or as [[thunder]])
|-
!scope="row"| Descriptor 
| FZ 
| Freezing; including: [[Freezing drizzle|FZDZ]], [[Freezing rain|FZRA]], [[Fog#Freezing fog|FZFG]] 
|-
!scope="row"| Precipitation 
| DZ 
| [[Drizzle]]
|-
!scope="row"| Precipitation 
| RA 
| [[Rain]]
|-
!scope="row"| Precipitation 
| SN 
| [[Snow]] ([[snowflake]]s)
|-
!scope="row"| Precipitation 
| SG 
| [[Snow grains]]
|-
!scope="row"| Precipitation 
| GS 
| [[Graupel]] {{small|[{{Langx|fr|Grésil|link=no}}]}}, snow pellets and/or small hail (not in the US).<ref group="note" name="SmallHail">In the US small hail is included with regular hail and the Remarks section is used saying "GR LESS THAN 1/4".</ref><ref>{{Cite web|url=http://www.faa.gov/documentLibrary/media/Notice/N_JO_7900.11.pdf|title=METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR)}}</ref> Elsewhere hail is GR when it is 5&nbsp;mm or greater<ref name="manobs10">[https://www.canada.ca/en/environment-climate-change/services/weather-manuals-documentation/manobs-surface-observations/recording-hourly-form-63-2322.html#ch1002 10.2 Section II – hourly observations "UTC"]. See 10.2.10 Column 32 – weather and obstructions to vision.</ref> Outside of the US when the hail is less than 5&nbsp;mm the code GS is used.<ref name="manobs10"/>) 
|-
!scope="row"| Precipitation 
| GR 
| [[Hail]] {{small|[{{Langx|fr|Grêle|link=no}}]}} (in the US includes small hail) <ref group="note" name="SmallHail" />
|-
!scope="row"| Precipitation 
| PL 
| [[Ice pellets]]
|-
!scope="row"| Precipitation 
| IC 
| [[Diamond dust|Ice crystals]]
|-
!scope="row"| Precipitation 
| UP 
| Unknown precipitation
|-
!scope="row"| Obscuration 
| FG 
| [[Fog]] ([[visibility]] less than 1&nbsp;km)
|-
!scope="row"| Obscuration 
| BR 
| [[Mist]] {{small|[{{Langx|fr|Brume|link=no}}]}} (due to water droplets, visibility between 1 and 5&nbsp;km)<ref group="note" name="BRHZ" />
|-
!scope="row"| Obscuration 
| HZ 
| [[Haze]] (due to dry particulates, visibility between 1 and 5&nbsp;km)<ref group="note" name="BRHZ">If the difference between temperature and dewpoint is less than or equal to 2°C, the station reports the condition as haze; else mist is reported.</ref><ref name="AWH" />{{rp|3}}
|-
!scope="row"| Obscuration 
| VA 
| Volcanic ash
|-
!scope="row"| Obscuration 
| DU 
| Widespread dust
|-
!scope="row"| Obscuration 
| FU 
| Smoke {{small|[{{Langx|fr|Fumée|link=no}}]}}
|-
!scope="row"| Obscuration 
| SA 
| Sand
|-
!scope="row"| Obscuration 
| PY 
| Spray, only coded as BLPY
|-
!scope="row"| Other 
| SQ 
| [[Squall]]
|-
!scope="row"| Other 
| PO 
| Dust {{small|[{{Langx|fr|Poussière|link=no}}]}} or [[Dust devil|sand whirls]]
|-
!scope="row"| Other 
| DS 
| [[Dust storm|Duststorm]]
|-
!scope="row"| Other 
| SS 
| [[Dust storm|Sandstorm]]
|-
!scope="row"| Other 
| FC 
| [[Funnel cloud]]
|-
!scope="row"| Time 
| B 
| Began at time
|-
!scope="row"| Time 
| E 
| Ended at time
|-
!scope="row"| Time 
| 2 digits 
| Minutes of current hour
|-
!scope="row"| Time 
| 4 digits 
| Hour/minutes Zulu time
|}

=== US METAR abbreviations ===
The following METAR abbreviations are used in the United States; some are used worldwide:<ref name="NWS-METAR+TAF List" />

'''METAR and TAF abbreviations and acronyms:'''
{| class="wikitable"
!scope="col"| Abbreviation
!scope="col"| Meaning
!scope="col"| Abbreviation
!scope="col"| Meaning
|-
|$ || maintenance check indicator || / || indicator that visual range data follows; separator between temperature and dew point data.
|-
|ACC || [[Altocumulus castellanus cloud|altocumulus castellanus]] ||ACFT MSHP || aircraft mishap
|-
|ACSL || altocumulus standing [[lenticular cloud]] || ALP || airport location point
|-
|ALQDS || all quadrants (official) || ALQS || all quadrants (unofficial)
|-
|AO1 || automated station without precipitation discriminator ||AO2 || automated station with precipitation discriminator
|-
|APCH || approach ||APRNT || apparent
|-
|APRX || approximately ||ATCT || airport traffic [[control tower]]
|-
|AUTO || fully automated report ||C || center (with reference to runway designation)
|-
|CA || cloud-air [[lightning]] || CB || [[cumulonimbus cloud]]
|-
|CBMAM || cumulonimbus [[mammatus cloud]] ||CC || cloud-cloud lightning
|-
|CCSL || [[Cirrocumulus cloud|cirrocumulus]] standing [[lenticular cloud]] || cd || [[candela]]
|-
|CG || cloud-ground lightning ||CHI || cloud-height indicator
|-
|CHINO || sky condition at secondary location not available || CIG || ceiling
|-
|CONS || continuous||COR || correction to a previously disseminated observation
|-
|DOC || [[United States Department of Commerce|Department of Commerce]]||DOD || [[United States Department of Defense|Department of Defense]]
|-
|DOT || [[United States Department of Transportation|Department of Transportation]]||DSIPTG || dissipating
|-
|DSNT || distant||DVR || dispatch visual range
|-
|E || east, ended, estimated ceiling (SAO)||FAA || [[Federal Aviation Administration]]
|-
|FIBI || filed but impracticable to transmit || FIRST || first observation after a break in coverage at manual station
|-
|FMH-1 || Federal Meteorological Handbook No.1, Surface Weather Observations & Reports (METAR) ||FMH2 || Federal Meteorological Handbook No.2, Surface Synoptic Codes
|-
|FROPA || [[Weather front|frontal]] passage || FROIN || frost on the indicator 
|-
|FRQ || frequent ||FT || [[Foot (length)|feet]]
|-
|FZRANO || freezing rain sensor not available || G || gust
|-
|HLSTO || hailstone || ICAO || [[International Civil Aviation Organization]]
|-
|INCRG || increasing || INTMT || intermittent
|-
|KT || [[Knot (unit)|knots]] || L || left (with reference to runway designation)
|-
|LAST || last observation before a break in coverage at a manual station || LST || local standard time
|-
|LTG || [[lightning]] || LWR || lower
|-
|M || minus, less than || MAX || maximum
|-
|METAR || routine weather report provided at fixed intervals || MIN || minimum
|-
|MOV || moved/moving/movement || MT || [[mountain]]s
|-
|N || north || N/A || not applicable
|-
|NCDC || [[National Climatic Data Center]] || NE || northeast
|-
|NOS || [[National Ocean Service]] || NOSPECI || no SPECI reports are taken at the station
|-
|NOTAM || [[NOTAM|Notice to Airmen]] || NW || northwest
|-
|NWS || [[National Weather Service]] ||OCNL || occasional
|-
|OFCM || Office of the Federal Coordinator for Meteorology ||OHD || overhead
|-
|OVR || over||P || indicates greater than the highest reportable value
|-
|PCPN || [[Precipitation (meteorology)|precipitation]]||PK WND || peak wind
|-
|PNO || precipitation amount not available||PRES || [[Atmospheric pressure|pressure]]
|-
|PRESFR || [[Atmospheric pressure|pressure]] falling rapidly||PRESRR || [[Atmospheric pressure|pressure]] rising rapidly
|-
|PWINO || precipitation identifier sensor not available||R || right (with reference to runway designation), [[runway]]
|-
|RTD || Routine Delayed (late) observation||RV || reportable value
|-
|RVR || [[Runway visual range]]||RVRNO || [[Runway visual range|RVR]] system values not available
|-
|RWY || [[runway]]||S || south
|-
|SCSL || [[Stratocumulus cloud|stratocumulus]] standing [[lenticular cloud]] || SE || southeast
|-
|SFC || surface, ''i.e.'', ground level) ||SLP || [[Atmospheric pressure|sea-level pressure]]
|-
|SLPNO || [[Atmospheric pressure|sea-level pressure]] not available||SM || [[Mile#Statute mile|statute miles]]
|-
|SNINCR || snow increasing rapidly || SOG || snow on the ground
|-
|SPECI || an unscheduled report taken when certain criteria have been met ||STN || station
|-
|SW || southwest ||TCU || [[towering cumulus]]
|-
|TS || [[thunderstorm]] ||TSNO || [[thunderstorm]] information not available
|-
|TWR || [[Control tower|tower]] ||UNKN || unknown
|-
|UTC || [[Coordinated Universal Time]]||V || variable
|-
|VIS || [[visibility]]||VISNO || visibility at secondary location not available
|-
|VR || visual range||VRB || variable
|-
|W || west ||WG/SO || Working Group for Surface Observations
|-
|WMO || [[World Meteorological Organization]] ||WND || [[wind]]
|-
|WS || [[wind shear]] ||WSHFT || wind shift
|-
|Z || Zulu, ''i.e.'', [[Coordinated Universal Time]]
|}

=== US METAR numeric codes ===
Additional METAR numeric codes listed after RMK.<ref name="NWS-METAR+TAF List" />

{| class="wikitable"
|+
|-
!scope="col"| Code
!scope="col"| Description
|-
!scope="row"| 11234
| 6-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 {{convert|-23.4|°C|0}}.
|-
!scope="row"| 20123
| 6-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 {{convert|12.3|C|0}}.
|-
!scope="row"| 4/012
| Total 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.
|-
!scope="row"| 402340123
| 24-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 {{convert|23.4|and|12.3|C|0}}.
|-
!scope="row"| 52006
| 3-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 {{convert|0.6|mb|inHg}}.<ref>{{Cite web|url=https://weather.cod.edu/notes/metar.html|title=Metar Help|website=College of DuPage}}</ref>
|-
!scope="row"| 60123
| 3- 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 {{convert|1.23|in|mm}} of rain.
|-
!scope="row"| 70246
| 24-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 {{convert|2.46|in|mm}} of rain.
|-
!scope="row"| 8/765
| Cloud cover using WMO code. Follows RMK starting with 8/ followed by a 3 digit number representing WMO cloud codes.
|-
!scope="row"| 98060
| Duration 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.
|-
!scope="row"| 931222
| Snowfall 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 {{convert|22.2|in|mm}} of snowfall.
|-
!scope="row"| 933021
| Liquid 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 {{convert|2.1|in|mm}} SWE.
|}

==See also==
<!-- New links in alphabetical order please -->
* [[BUFR]]
* [[CLIMAT]]
* [[GAFOR]]
* [[IWXXM]]
* [[Surface weather observation]]
* [[SYNOP]]
* [[Terminal Aerodrome Forecast|TAF]]
* [[Trend type forecast]]

== Notes ==
{{reflist|group=note}}

==References==
{{Reflist}}

== External links ==
{{wiktionary|METAR|SPECI}}
;Decoding
*[https://e6bx.com/metar-decoder/ E6BX Online Metar Decoder]
*[http://www.flightutilities.com/MRonline.aspx FlightUtilities.com METAR and TAF online decoder]

;Format specifications
*[https://web.archive.org/web/19990420051036/http://www.ofcm.gov/fmh-1/fmh1.htm OFCM.gov]&nbsp;— US Federal Meteorological Handbook No. 1&nbsp;— Surface Weather Observations and Reports (September 2005). Complete documentation on the METAR format, PDF.

;Software libraries
*[http://search.cpan.org/search?query=metar&mode=all Perl modules for parsing METAR reports] at the [[CPAN]] site
*[http://sourceforge.net/projects/phpweather/ PhpWeather] is a [[PHP]] application (with a [[GNU General Public License]]) that parses METAR reports.
*[http://www.schwarzvogel.de/software-pymetar.shtml pymetar] and [https://pypi.python.org/pypi/metar/ metar]&nbsp;— [[Python (programming language)|Python]] libraries for METAR fetching and parsing
*[https://sites.google.com/view/atmospherictide/home Using METAR data to see the Atmospheric Tide]

;Current reports
*[http://www.aviationweather.gov/metar Selection of worldwide METAR reports from the US NOAA]
*[http://www.rap.ucar.edu/weather/surface/stations.txt List of Stations in NOAA database.] Use CTRL+F to search for a station. Input four-letter ICAO identifier to [http://weather.noaa.gov/weather/metar.shtml Worldwide METAR Data Access from the US NOAA].
*[http://www.checkwx.com CheckWX]&nbsp;— Raw and decoded METARs, METAR cycles, trends and graphs for locations worldwide

{{Meteorological variables}}
{{Meteorological equipment}}
{{Earth-based meteorological observation}}

{{DEFAULTSORT:Metar}}
[[Category:1968 introductions]]
[[Category:Aviation meteorology]]
[[Category:Earth sciences data formats]]
[[Category:Aviation publications]]