Weather & Decoding

METAR Decoder

Paste any raw METAR to get a complete plain-English breakdown of every field including the full remarks section — with an annotated hover display, individual decoded boxes for each code, and automatic flight category determination.

METAR Decoder

Paste a raw METAR below — hover over each token in the annotated display to see what it means

Usage Guide

How to use the METAR decoder

Four steps from raw METAR to a complete weather picture.

01

Obtain the raw METAR

Copy the full raw METAR string from your weather source — ATIS, ACARS, aviation weather website, or flight planning app. Include everything from the station identifier through the end of the remarks section.

02

Paste and decode

Paste the METAR into the input box and click Decode. Accepts ICAO worldwide format (Q prefix altimeter) and US domestic format (A prefix). The leading METAR or SPECI type indicator is optional.

03

Hover the annotated display

The raw METAR is shown with every token as a hoverable element on a grey background. Hover any token to see a tooltip with the field name and a plain-English explanation of that specific value.

04

Read every decoded box

Every field appears as a box showing the raw code at the top in bold, followed by the field label and plain-English value. Body fields and remarks are shown in separate grids of three boxes per row.

Format Reference

Complete METAR format — every field explained

Every METAR follows a strict sequential field order defined by ICAO Annex 3 / WMO No. 49. The numbered tokens in the example below correspond to the # column in the table. Remarks (RMK) are a US domestic extension not part of standard ICAO format.

Annotated example — hover over numbers matches table rows
1 KBOS 2 271454Z 3 AUTO 4 27018G25KT 5 210V270 6 2500 7 R04R/1200FT 8 +RA 9 BKN025CB 10 08/06 11 Q1008 12 NOSIG 13 RMK
14 AO2 15 PK WND 28032/1420 16 SFC VIS 10 26 DZE36RAB36E39 27 OCNL LTGICCC DSNT E 18 SLP958 22 T01220028 20 10231 21 20089 23 53036 19 60015 25 83311195 24 413230322 29 VIRGA DSNT SE 30 ACSL DSNT W 31 PWINO 31 TSNO 33 $

Fields 1–12 are ICAO standard (Annex 3 §15). Field 13 (RMK) opens the US remarks section; fields 14–33 are coded remarks within RMK (FAA Order JO 7900.5D).

# Field Format / Code ICAO-compliant description
1 Station Identifier CCCC (4-letter ICAO code) Four-character ICAO aerodrome designator. First letter(s) indicate the ICAO region: K = contiguous USA, P = Pacific/Alaska, EG = UK, LF = France, YS = Australia, VH = Hong Kong. Always 4 characters. (ICAO Annex 3 §15.2)
2 Date & Time DDHHmmZ Day of month (DD), hour (HH), minute (mm) in UTC, followed by Z (Zulu). Always UTC — never local time. Example: 271454Z = 27th at 14:54 UTC. (ICAO Annex 3 §15.3)
3 Report Modifier AUTO  or  COR AUTO: fully automated observation, no human augmentation. Some phenomena (lightning, partial obscuration, ice crystals) may not be detected. COR: corrected report superseding a previous erroneous METAR for the same station/time. Absent = human observer present. (ICAO Annex 3 §15.4)
4 Wind DDDffGffmaxKT or MPS
or VRB ffKT
or 00000KT		 Direction is always in degrees TRUE — not magnetic. (ICAO Annex 3 §15.6.2). DDD = direction wind is blowing FROM (000–360°). ff = 10-minute mean speed. G = gust indicator. ffmax = maximum 3-second gust in past 10 minutes. KT = knots, MPS = metres per second. VRB = direction variable with no prevailing direction (speed ≤3 kt or varying ≥60° with no prevailing direction). 00000KT = calm (<3 kt). Do not confuse wind direction (TRUE) with runway heading (magnetic).
5 Wind Variable Direction DDDVDDDfollowing wind group When mean wind direction varies by 60° or more, the two extreme directions are reported in clockwise order: e.g. 210V270. Both limits are in degrees TRUE. Reported in addition to the mean direction in the wind group. No speed threshold applies — this is purely a direction variability observation. (ICAO Annex 3 §15.6.2.4)
6 Prevailing Visibility VVVVin metres or n SM (US) ICAO: prevailing visibility in metres, 4 digits. 0000 = <50 m. 9999 = 10 km or more. Prevailing = greatest value achieved over more than half the horizon circle (not necessarily uniform). US format: statute miles with fractions (e.g. 1 1/2SM). P prefix = more than (P6SM = >6 SM). CAVOK may replace this group when all CAVOK criteria are met. (ICAO Annex 3 §15.6.3)
CAVOK CAVOK CAVOK replaces fields 6, 7, and 8 Ceiling and Visibility OK — reported when ALL three conditions are simultaneously satisfied: (1) Visibility ≥10 km; (2) No cloud below 5,000 ft AGL or below the Minimum Sector Altitude (MSA), whichever is higher, AND no cumulonimbus (CB) or towering cumulus (TCU) at any level; (3) No significant weather phenomena (precipitation, obscuration, or other significant phenomena). CAVOK is not used in US domestic METARs (SKC/CLR used instead). (ICAO Annex 3 §15.6.5)
7 Runway Visual Range (RVR) RDDL/[M|P]VVVVi[FT] Reported when prevailing visibility is below 1,500 m (or 6,000 ft in US). R = runway. DD = runway designator number. L/C/R = Left/Centre/Right for parallel runways. M = less than (minimum sensor limit). P = more than (maximum sensor limit). VVVV = RVR value in metres (or feet with FT suffix). i = trend: U = increasing, D = decreasing, N = no change. Measured by forward-scatter transmissometers positioned at runway touchdown zone, midpoint, and stopend. (ICAO Annex 3 §15.6.4)
8 Present Weather [intensity][descriptor][phenomenon] Intensity: − (light), no qualifier (moderate), + (heavy), VC (in vicinity, 5–10 SM from station).
Descriptor codes: MI shallow, BC patches, PR partial, DR low drifting, BL blowing, SH showers, TS thunderstorm, FZ freezing.
Phenomenon codes: RA rain, SN snow, DZ drizzle, SG snow grains, IC ice crystals, PL ice pellets, GR hail (≥5mm), GS small hail, UP unknown precipitation (AUTO), FG fog (vis <1,000 m), BR mist (1,000–9,999 m), HZ haze, FU smoke, SA sand, DU dust, VA volcanic ash, SQ squall, FC funnel cloud/tornado, DS duststorm, SS sandstorm, PO dust/sand whirls.
Multiple phenomena may be combined: TSRA = thunderstorm with rain; FZRA = freezing rain; BLSN = blowing snow. (ICAO Annex 3 §15.6.6 + WMO No. 306 Vol. I)
9 Sky Condition CCChhh[CB|TCU]
or VVhhh
or SKC/CLR/NSC/NCD		 CCC = coverage: FEW (1–2 oktas), SCT scattered (3–4), BKN broken (5–7), OVC overcast (8). hhh = cloud base height in hundreds of feet AGL (e.g. BKN025 = 2,500 ft). CB = cumulonimbus appended when identified. TCU = towering cumulus. VV = vertical visibility into a complete obscuration — acts as the ceiling. SKC = sky clear (human report). CLR = no cloud below 12,000 ft (AUTO). NSC = no significant cloud (no cloud below 5,000 ft or MSA, no CB/TCU, no obscuration). NCD = no cloud detected (automated).
Ceiling = lowest BKN or OVC layer (or VV). FEW and SCT are NOT ceilings. (ICAO Annex 3 §15.6.7)
10 Temperature & Dew Point TT/TdTd Temperature (TT) and dew point (TdTd) in degrees Celsius, rounded to nearest whole degree. M prefix = minus (negative): M05/M08 = −5°C / −8°C. Temperature–dew point spread: <3°C = high risk of fog or low stratus. <2°C = near-saturation conditions. (ICAO Annex 3 §15.6.8)
11 Altimeter Setting QHHHH (hPa) or AHHHH (inHg) Q prefix = QNH in hectopascals (hPa). Example: Q1013 = 1013 hPa. ISA standard = 1013.25 hPa — Q1013 is slightly below standard. A prefix = US altimeter in inHg × 100: A2992 = 29.92 inHg. Set this value on the altimeter subscale before descent through the transition altitude so the altimeter reads height AMSL on the ground. (ICAO Annex 3 §15.6.9)
12 Trend Forecast
(NOSIG / BECMG / TEMPO)		 NOSIG
BECMG [change groups]
TEMPO [change groups]		 ICAO trend-type landing forecast appended to METAR — covers the 2-hour period following the observation time. (ICAO Annex 3 §15.11). NOSIG = no significant change expected in any element. BECMG = conditions gradually changing to those specified and expected to persist (transition period indicated by AT, FM, or TL). TEMPO = conditions temporarily expected for periods <60 min each and <50% of the total period. Change groups use the same wind/visibility/weather/cloud format as the METAR body. Trend is an ICAO standard element — present in most international METARs (EGLL, LFPO, etc.) but NOT in US domestic METARs.
13 Remarks (RMK) RMK [coded tokens] (US only) US domestic extension (FAA Order JO 7900.5D) — not part of ICAO standard METAR. Begins with the literal token RMK. Contains additional coded and free-text information. Common coded remarks are listed below.
14 Station Type AO1 or AO2 AO1 = automated station without precipitation discriminator (cannot distinguish rain from snow, may report UP — unknown precipitation). AO2 = automated station with precipitation discriminator.
15 Peak Wind PK WND DDDff/HHmm Highest wind gust recorded since the last METAR. DDD = direction in degrees TRUE. ff = speed in knots. HHmm = UTC time of peak. Example: PK WND 28032/1420 = peak gust from 280° TRUE at 32 kt at 14:20 UTC.
16 Surface Visibility SFC VIS n Visibility measured at surface level (ground observer), in statute miles. May differ from prevailing visibility in a non-uniform weather situation.
17 Tower Visibility TWR VIS n Visibility as measured from the control tower level, in statute miles.
18 Sea Level Pressure SLPnnn Sea-level pressure in hPa to one decimal place. Leading digit is inferred: value ≥55.0 → prefix 9 (e.g. SLP958 = 995.8 hPa); value <55.0 → prefix 10 (e.g. SLP012 = 1001.2 hPa). More precise than the standard Q/A altimeter group.
19 Precipitation — Last 6 Hours 6xxxx 6 followed by 4 digits = total precipitation in hundredths of an inch in the 6 hours preceding this observation. 60000 = 0.00 in (trace or none). 60015 = 0.15 in. 6//// = unmeasurable or missing.
20 6-Hour Max Temperature 1xxxx Maximum temperature in the 6 hours before this observation. Digit 2 = sign (0 = positive, 1 = negative). Digits 3–5 = tenths of °C. Example: 10161 = maximum 16.1°C.
21 6-Hour Min Temperature 2xxxx Minimum temperature in the 6 hours before this observation. Same format as 1xxxx. Example: 20056 = minimum 5.6°C.
22 Precise Temperature Txxxxxxxx High-precision temperature and dew point from sensor. Format: T + [0/1] + 3 digits + [0/1] + 3 digits. Sign digits: 0 = positive, 1 = negative. Values in tenths of °C. Example: T01220028 = temp 12.2°C, dew point 2.8°C.
23 3-Hour Pressure Tendency 5xxxx WMO pressure tendency. Digit 2 = characteristic code (0–8, see WMO Code Table 0200). Digits 3–5 = amount of pressure change in tenths of hPa over past 3 hours. Example: 53036 = characteristic 3 (increasing steadily), change 3.6 hPa.
24 24-Hour Max / Min Temperature 4xxxxxxxxx (9 digits) 24-hour maximum and minimum temperature. Format: 4 + [0/1] + max(3 digits) + [0/1] + min(3 digits), all in tenths of °C. Example: 413230322 = 24-hr max −32.3°C, min +32.2°C.
25 Runway State (MOTNE/GRF) RRERC RBrBr fnfn (8 digits) 8-digit runway condition code per Global Reporting Format (GRF). RR = runway designator (>50 = runway + R suffix, e.g. 33R). E = deposit type (0=clear, 1=damp, 2=wet, 3=rime, 4=dry snow, 5=wet snow, 6=slush, 7=ice, 8=compacted snow, 9=frozen ruts). R = extent of contamination (1=≤10%, 2=11–25%, 5=26–50%, 9=51–100%). BrBr = depth in mm (99=not measurable). fnfn = friction/braking action (91=poor, 92=medium/poor, 93=medium, 94=medium/good, 95=good).
26 Weather Event Times (DZ|RA|SN|etc.)(B|E)HHmm Begin (B) and end (E) times of precipitation phenomena since the last METAR. HHmm = UTC time, or mm = minutes past the current hour. Multiple events may be concatenated: DZE36RAB36E39 = drizzle ended at :36, rain began at :36, rain ended at :39.
27 Lightning (OCNL|FRQ|CONS) LTGtype [DSNT] [direction] Lightning observed at or near the station. Frequency: OCNL occasional, FRQ frequent, CONS continuous. Type codes follow LTG: IC in-cloud, CC cloud-to-cloud, CG cloud-to-ground, CA cloud-to-air. Location: DSNT = distant (>10 SM), OHD = overhead; compass direction (N, NE, E, SE, S, SW, W, NW, or range e.g. E-SE).
28 Runway-Specific Wind RWYnn[L|C|R] DDDffKT [DDDVDDDrange] Wind observation specific to a particular runway. Direction in degrees TRUE. Reported when runway wind differs significantly from the station wind or for multiple active runways. Variable direction range may follow if applicable. Example: RWY17L 23006KT = runway 17L, wind 230° TRUE at 6 kt.
29 VIRGA VIRGA [DSNT direction] Precipitation is falling from clouds but evaporating in the sub-cloud layer before reaching the surface. May indicate dry microbursts. Location given by DSNT + compass direction.
30 ACSL ACSL [DSNT dir] [MOV dir] Altocumulus Standing Lenticular — stationary lens-shaped cloud indicating mountain wave / lee wave activity. Indicates potential severe turbulence and significant icing. MOV = direction of motion of the wave system.
31 Sensor Status PWINO / TSNO / RVRNO / FZRANO PWINO = Present Weather Identifier Not Operating (precipitation type sensor offline). TSNO = Thunderstorm Information Not Available (no lightning sensor). RVRNO = RVR transmissometer offline. FZRANO = freezing rain sensor unavailable.
32 Pressure Change PRESFR / PRESRR PRESFR = Pressure Falling Rapidly (≥2 hPa in the past hour). PRESRR = Pressure Rising Rapidly. Indicates a rapidly changing synoptic situation — significant for altimeter setting currency.
33 Maintenance Required $ Dollar sign appended to indicate the ASOS/AWOS system requires maintenance on one or more sensors. Data reliability may be degraded. The specific sensor requiring maintenance is not identified in the METAR itself.

ICAO Annex 3 = Meteorological Service for International Air Navigation. WMO No. 49 = Technical Regulations. WMO No. 306 = Manual on Codes (present weather table). FAA Order JO 7900.5D = US Surface Weather Observations (governs RMK section).

Flight Categories

How a METAR determines the aviation flight category

The most restrictive of ceiling or visibility governs. Scattered (SCT) and few (FEW) layers never constitute a ceiling.

VFR
Ceiling > 3,000 ft
Visibility > 5 SM

Standard visual conditions. No IR required.

MVFR
Ceiling 1,000–3,000 ft
Visibility 3–5 SM

Marginal. Legal for VFR but caution required.

IFR
Ceiling 500–999 ft
Visibility 1–<3 SM

Instrument conditions. IR and clearance required.

LIFR
Ceiling < 500 ft
Visibility < 1 SM

Low IFR. Precision approaches likely required.

Common Questions

Frequently asked questions about METARs

METAR stands for Meteorological Aerodrome Report (from the French Météorologique Aviation Régulière). It is the standard format for aviation surface weather observations issued by certified meteorological observers or automated surface observation systems (ASOS/AWOS). The METAR format is defined by ICAO Annex 3 and WMO Publication No. 49 and is used worldwide with minor national variations.

A routine METAR is issued once per hour, typically at 50 to 55 minutes past the hour so it is available by the top of the hour. At busier airports, METARs may be issued every 30 minutes. An unscheduled SPECI is issued whenever significant changes occur: wind direction shift of 60° or more, wind speed change of 10 knots or more, visibility crossing a key threshold, or ceiling change crossing 300, 600, 1,500, or 3,000 feet thresholds.

A METAR follows a strict field order defined by ICAO: (1) report type, (2) station identifier, (3) date/time UTC, (4) AUTO or COR modifier, (5) wind, (6) visibility, (7) RVR, (8) present weather, (9) sky condition, (10) temperature/dew point, (11) altimeter setting, (12) recent weather, (13) wind shear, (14) remarks. Fields are separated by spaces. Missing fields are omitted entirely.

AUTO indicates the report was generated by an automated surface observation system without human augmentation. Automated stations may not report all weather phenomena accurately. AO1 in remarks means automated station without precipitation discriminator; AO2 means automated station with precipitation discriminator capable of distinguishing rain from snow.

Cloud cover uses four descriptors: FEW (1-2 oktas), SCT scattered (3-4 oktas), BKN broken (5-7 oktas), and OVC overcast (8 oktas). Height is in hundreds of feet AGL — BKN025 means broken clouds at 2,500 ft. The ceiling is the lowest BKN or OVC layer. CB (cumulonimbus) or TCU (towering cumulus) are appended when convective cloud is present.

RVR (Runway Visual Range) is the distance a pilot on the runway centreline can see the surface markings or lights. It is measured by transmissometers and reported in METAR when visibility is below 1,500 metres. Format: RDDL/VVVVi where DD is runway number, VVVV is the range value, and i is trend (U improving, D decreasing, N no change). The P prefix means more than, M means less than.

Present weather uses intensity qualifiers (- light, no qualifier = moderate, + heavy) combined with descriptor codes (TS thunderstorm, SH showers, FZ freezing, BL blowing) and phenomenon codes (RA rain, SN snow, DZ drizzle, FG fog, BR mist, HZ haze). Multiple phenomena can be combined: TSRA = thunderstorm with rain; FZRA = freezing rain; -SHSN = light snow showers.

The altimeter setting calibrates the altimeter to show altitude above sea level. Q prefix = QNH in hPa (e.g. Q1013). A prefix = altimeter in inches of mercury x100 (e.g. A2992 = 29.92 inHg). Before descending through the transition altitude, pilots set the destination QNH so the altimeter reads field elevation on touchdown.

SLP (Sea Level Pressure) in remarks gives the precise sea-level pressure in hPa to one decimal place. SLP958 means 995.8 hPa — the leading digit is inferred: values 550-999 get prefix 9; values 000-549 get prefix 10. So SLP958 = 995.8 hPa and SLP012 = 1001.2 hPa. SLP provides higher precision than the standard Q-group altimeter setting.

Flight category is determined by ceiling and visibility. VFR: ceiling above 3,000 ft and visibility above 5 SM. MVFR: ceiling 1,000–3,000 ft or visibility 3–5 SM. IFR: ceiling 500–999 ft or visibility 1 to less than 3 SM. LIFR: ceiling below 500 ft or visibility below 1 SM. The most restrictive of ceiling or visibility determines the category.

Use the METAR data in these tools

TAF Decoder

After decoding the current METAR, decode the TAF to understand how conditions are forecast to change over the next 9 to 30 hours.

TAF Decoder →