How to read METAR
Updated at: 2025-12-01 11:24
How to read METAR What is a METAR and why it matters The standard METAR structure at a glance Step-by-step decoding of a sample METAR 1. Type and station identifier 2. Time of observation (date and Zulu time) 3. Wind: direction, speed, variability, and gusts 4. Visibility and special values like CAVOK 5. Runway Visual Range (RVR) 6. Present weather codes 7. Cloud layers: coverage, base, and significance 8. Temperature and dew point 9. QNH / altimeter setting 10. Trend information: NOSIG, BECMG, TEMPO Understanding the remarks section (RMK) Common variations and regional differences North American vs. ICAO style AUTO, COR, NIL and missing elements Practical tips to read METARs faster and more accurately 1. Scan in a fixed order 2. Link METAR elements to your minima and performance 3. Watch for red-flag combinations 4. Train with real-world examples Summary: turning METAR code into clear decisions
What is a METAR and why it matters
A METAR is an official aviation routine weather report, usually issued every hour, describing the actual conditions at an aerodrome. Unlike a TAF (Terminal Aerodrome Forecast), which is a forecast, a METAR tells you what the weather is right now or very recently observed at the station.
For pilots, METARs are the primary tool to assess whether current conditions meet VFR or IFR minima, what kind of approach is realistic, whether de-icing might be required, and how much performance margin you can expect for takeoff and landing. Controllers and dispatchers use the same information to plan runway configurations, flow control, and alternates.
The good news: METARs follow a strict, globally standardised format defined by ICAO. Once you understand the sequence and a few abbreviations, the code becomes a compact, highly efficient way to communicate complex weather in a single line.
The standard METAR structure at a glance
Although local variations exist (especially in North America vs. pure ICAO format), most METARs follow this general order:
- Type and station: METAR or SPECI, plus ICAO airport code
- Time of observation: day and time in UTC
- Wind: direction and speed, including variability and gusts
- Visibility: prevailing visibility and, where used, minimum/sector visibility
- Runway Visual Range (RVR): if below certain thresholds
- Present weather: precipitation, obscuration, and significant phenomena
- Clouds: coverage, base, and significant cloud types
- Temperature and dew point
- Altimeter/QNH: pressure setting
- Recent weather, wind shear, trend and remarks: additional details and local notes
We will now decode a complete example line by line and then look at common variations and tricky parts you will encounter in real-world operations.
Step-by-step decoding of a sample METAR
Consider this example METAR:
METAR EDDM 011220Z 26012KT 220V290 9999 -RA SCT020 BKN035 18/14 Q1013 NOSIG
1. Type and station identifier
METAR simply tells you this is a routine hourly observation (as opposed to a SPECI, which is a special report issued when weather changes significantly between routine times).
EDDM is the four-letter ICAO code for Munich Airport. Always think in ICAO, not IATA: EGLL for London Heathrow, KJFK for New York JFK, YSSY for Sydney, etc. If you are unsure about a code, cross-check with your charts or EFB before acting on the report.
2. Time of observation (date and Zulu time)
011220Z breaks down as:
Always convert this to your local time zone mentally or in your EFB. The report can be up to 60 minutes old in routine conditions; in fast-changing weather, also look for SPECI reports and the trend line (NOSIG, BECMG, TEMPO, etc.).
3. Wind: direction, speed, variability, and gusts
26012KT 220V290 tells you:
- 26012KT – wind from 260° at 12 knots
- Direction is always the direction the wind is coming from, in degrees true in METARs (tower reports to aircraft use magnetic for runway alignment).
- KT – units are knots (sometimes MPS for metres per second in some states).
- 220V290 – wind direction varying between 220° and 290°. This is reported when the variation is 60° or more and the mean speed is above a threshold.
If gusts are present, you might see something like 26012G25KT (gusting 25 kt). For crosswind calculations, always consider the gust value, especially on short or contaminated runways.
4. Visibility and special values like CAVOK
9999 is the visibility group. In ICAO format, this means visibility 10 km or more. Some key patterns:
- 9999 – 10 km or more
- 8000 – 8 km
- 3000 – 3 km
- 0500 – 500 m
- 0500NW – 500 m in the northwest sector (where sector visibility is reported)
Instead of a number, you may see CAVOK (Ceiling And Visibility OK). This means: visibility 10 km or more, no cloud below 5 000 ft (or below the highest minimum sector altitude), and no significant weather like precipitation, thunderstorms, or low-level wind shear. Do not confuse CAVOK with 2clear sky2 6re can still be high cloud or weather above those thresholds.
5. Runway Visual Range (RVR)
When visibility is low, you may see runway visual range groups like:
R26L/0600D
RVR is critical for low-visibility operations and approach minima. Always cross-check RVR against the published minima for the approach category and your aircraft/operator limitations before committing to an approach or departure.
6. Present weather codes
In our example, the weather group is -RA, which stands for light rain. Present weather codes follow a consistent logic: optional intensity, optional descriptor, then the phenomenon itself.
- Intensity:
- - – light
- (no sign) – moderate
- + – heavy
Multiple phenomena can be combined, for example +TSRA (heavy thunderstorm with rain) or -SN BR (light snow and mist). As a pilot, prioritise anything that affects visibility, runway condition, or airframe icing: fog, low cloud, heavy precipitation, thunderstorms, and freezing precipitation are the big ones.
7. Cloud layers: coverage, base, and significance
Our example shows SCT020 BKN035. Each cloud group has three parts: amount, type (implicitly), and height of the base in hundreds of feet above ground level (AGL).
- FEW – 1–2 oktas (eighths of sky) covered
- SCT – scattered, 3–4 oktas
- BKN – broken, 5–7 oktas (considered a ceiling)
- OVC – overcast, 8 oktas (also a ceiling)
- SCT020 – scattered cloud with base at 2 000 ft AGL
- BKN035 – broken cloud with base at 3 500 ft AGL (this is the ceiling)
Significant cloud types may be appended:
- CB – cumulonimbus (thunderstorm cloud)
- TCU – towering cumulus (strong vertical development, often a precursor to CB)
For example, BKN025CB would indicate a broken layer of cumulonimbus at 2 500 ft. From an operational standpoint, pay close attention to ceiling height relative to circuit altitude, minimum vectoring altitude, and approach minima.
You may also see:
- NSC – no significant cloud (no cloud below 5 000 ft and none of operational significance)
- NCD – no clouds detected (automated station could not detect any)
- VV/// – vertical visibility when the sky is obscured (e.g. in fog)
8. Temperature and dew point
In the sample METAR, 18\/14<\/b> means:
- 18 – temperature +18 °C
- 14 – dew point +14 °C
Negative values are prefixed with M for 1minus7. For example, M05/M10 means -5 6C temperature and -10 6C dew point.
The closer temperature and dew point are to each other, the more likely fog, low cloud, or mist will form, especially around sunset and during the night. A spread of 2 B0C or less is a strong warning flag for reduced visibility, which is critical for planning alternates and fuel.
9. QNH / altimeter setting
Q1013 is the QNH, the pressure setting to put on your altimeter so that it reads airfield elevation when on the ground. In ICAO format:
- Q1013 – 1013 hPa (hectopascals)
In North America and some other regions, you may see altimeter settings in inches of mercury, typically in the remarks section (e.g. A2992 for 29.92 inHg). When operating internationally, be very clear whether you are reading hPa or inches to avoid gross altitude errors.
10. Trend information: NOSIG, BECMG, TEMPO
At the end of our example, NOSIG means 2no significant change expected in the next two hours2. Trend information is a short-term forecast attached to the METAR, not a description of current conditions.
- NOSIG – no significant change
- BECMG – becoming (permanent or long-lasting change)
- TEMPO – temporary fluctuations expected
For example:
METAR EDDM 011220Z 26012KT 9999 -RA SCT020 BKN035 18/14 Q1013 TEMPO 3000 +TSRA BKN010CB
Understanding the remarks section (RMK)
After the main body, many METARs include a remarks section, starting with RMK. This part is less standardised internationally and often includes local or national-format information, but several common patterns are worth knowing.
- SLP – sea level pressure (e.g. SLP987 for 998.7 hPa)
- AO1/AO2 – type of automated station (US)
- PK WND 28035/20 – peak wind 35 kt from 280° at minute 20 past the hour
- RAB20 – rain began at 20 past the hour; RAE35 – rain ended at 35
- LTG DSNT SW – lightning distant southwest
- WIND SHEAR RWY26 – reported low-level wind shear on or near runway 26
For flight operations, pay particular attention to any mention of wind shear, thunderstorms, runway contamination, or significant changes that have not yet made it into the main METAR body. Remarks can provide an early warning before conditions officially cross reporting thresholds.
Common variations and regional differences
While ICAO provides a global standard, some regions use additional or slightly different conventions. Being aware of these prevents misinterpretation when you cross borders.
North American vs. ICAO style
In the United States and parts of Canada, METARs are mostly ICAO-compliant but include US-specific elements, especially in the remarks. You will also see altimeter settings in inches of mercury and different ways of reporting automated observations.
Example US-style METAR:
Key differences from the earlier ICAO example:
- 10SM – visibility in statute miles instead of metres/kilometres
- A2992 – altimeter 29.92 inHg instead of QNH in hPa
- RMK AO2 – automated station with a precipitation sensor
AUTO, COR, NIL and missing elements
You may encounter additional keywords around the METAR type:
If an element is not observed or not available, you may see placeholders like \/\/\/\/<\/b>. Do not guess missing values; if critical (for example, no cloud information in marginal conditions), consider the field effectively unknown and increase your safety margins or seek additional sources such as ATIS or pilot reports.
Practical tips to read METARs faster and more accurately
Beyond memorising codes, the real skill is extracting operational meaning quickly: can I depart, can I land, and what are the main risks? These habits help you turn raw METAR data into decisions.
1. Scan in a fixed order
Develop a consistent mental checklist when you read any METAR. For example:
- Time – how old is this report?
- Wind – direction, crosswind, gusts, variability vs. runway in use
- Visibility/RVR – legal minima and personal/company minima
- Clouds – ceiling vs. circuit altitude and approach minima
- Weather – precipitation, thunderstorms, icing risk
- Temperature/dew point – fog risk, performance, icing
- QNH – altitude reference, density altitude considerations
- Trend/remarks – is it getting better or worse?
Using the same order every time reduces the chance of missing something important under time pressure, for example a low RVR buried between other groups.
2. Link METAR elements to your minima and performance
Do not treat the METAR as abstract data. Constantly relate it to your aircraft, your procedures, and your skills:
- Compare crosswind and tailwind components to your certified and personal limits.
- Compare visibility and ceiling to approach minima and alternate requirements.
- Use temperature and QNH to estimate density altitude and takeoff/landing distance.
- Use dew point spread and trends to anticipate rapid changes around dawn/dusk.
This way, decoding the METAR is not the goal; safe, informed decision-making is.
3. Watch for red-flag combinations
Certain combinations of METAR elements should immediately raise your attention:
- Strong, gusty crosswinds plus wet or contaminated runway
- Low ceiling close to circling or approach minima
- Small temperature–dew point spread with light wind at night (fog risk)
- Thunderstorms (TS, CB) near the field with strong wind shifts
- Freezing precipitation (FZRA, FZDZ) or mixed rain/snow around 0 °C
When you see these, slow down your planning, consult TAFs and radar, and consider alternates and fuel more conservatively.
4. Train with real-world examples
The fastest way to become fluent in METAR reading is to decode real reports daily, not just in the simulator. Pick a few busy airports across different climates, grab their latest METARs and TAFs, and translate them into plain language. Then compare with ATIS or live camera feeds where available to build intuition.
For radio training specifically, practise reading METARs out loud and then summarising the operational impact in one or two sentences, just as you would brief your crew or instructor.
Summary: turning METAR code into clear decisions
For professional and enthusiast pilots alike, the key is not just reading the code, but linking every group to concrete operational questions: Can I safely depart or land? What will the approach look like? Do I need an alternate, more fuel, or a different runway? With regular practice on real-world examples, reading METARs becomes an automatic part of your preflight and in-flight decision-making toolkit.
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