How to Read a METAR: Every Field, in Order
A METAR looks like a password and reads like a sentence. Once you know the order of the groups, the line stops being code: it is an observation written the same way at every aerodrome on the planet, so that a report from Reykjavík and one from Jakarta can be read by the same person without translation.
The rule that makes it learnable is that the order never changes. Every group appears in the same place, and any group that is absent means there was nothing to say.
The worked example#
Take a routine report and walk through it. EGLL 121250Z 24012KT 9999 FEW035 SCT120 14/09 Q1013 NOSIG says: London Heathrow, on the 12th of the month at 12:50 UTC, wind from 240 degrees at 12 knots, visibility 10 km or more, a few clouds at 3,500 feet and scattered cloud at 12,000 feet, temperature 14 °C with a dew point of 9 °C, pressure 1013 hectopascals, no significant change expected in the next two hours.
Nothing in that line is optional decoration. Each group either narrows what can be flown or confirms that nothing is in the way.
The groups, in the order they appear#
| Group | Example | Reads as |
|---|---|---|
| Station | EGLL | ICAO identifier of the aerodrome |
| Day and time | 121250Z | 12th of the month, 12:50 UTC — always UTC |
| Wind | 24012G22KT | From 240° at 12 knots, gusting 22 |
| Visibility | 9999 / 1 1/2SM | 10 km or more; or one and a half statute miles |
| Present weather | -RA BR | Light rain and mist |
| Cloud | BKN012 SCT025CB | Broken at 1,200 ft, scattered cumulonimbus at 2,500 ft |
| Temperature / dew point | 14/09 | 14 °C, dew point 9 °C |
| Pressure | Q1013 / A2992 | QNH 1013 hPa; or 29.92 inHg |
| Trend | NOSIG / TEMPO 3000 RA | No significant change; or a temporary deterioration |
AUTO before the wind group means there was no human observer. COR means the report replaces an earlier one — read the corrected version and discard what you remember.
Wind, and why the small print matters#
The wind group carries more decisions than any other. Direction is given in degrees true to the nearest ten, speed in knots, and a gust is appended after a G. VRB replaces the direction when the wind is genuinely variable below six knots. A separate group such as 240V300 means the direction has been swinging between those bearings, which matters far more than the average suggests: a runway that is inside limits at 240° may not be at 300°.
- 00000KT — calm.
- VRB03KT — variable direction, three knots.
- 24012G28KT — from 240° at 12, gusting 28; the gust is the number the crosswind calculation uses.
- 240V300 — direction varying across that arc.
- P99KT — speed above 99 knots, which is rare and never routine.
Wind in a METAR is degrees TRUE. The runway numbers and the tower are magnetic. In most of the world the difference is small; near the poles it is not.
Cloud, coverage and the ceiling#
Cloud is reported as coverage plus height in hundreds of feet above aerodrome elevation, lowest layer first. Coverage is measured in oktas — eighths of the sky. Only BKN and OVC count as a ceiling, and the ceiling is what most approach minimums are written against.
| Code | Coverage | Counts as a ceiling? |
|---|---|---|
| FEW | 1–2 oktas | No |
| SCT | 3–4 oktas | No |
| BKN | 5–7 oktas | Yes |
| OVC | 8 oktas | Yes |
| NSC / NCD | No significant cloud / none detected | No |
| VV003 | Sky obscured, vertical visibility 300 ft | Treated as a ceiling |
CB and TCU are appended to a layer — SCT025CB — and they are the only cloud types a METAR reports, because they are the only two that change what you do.
Temperature, dew point and what they warn about#
The pair is written temperature/dew point in whole degrees Celsius, with M for minus. The gap between them is the single most useful derived number in the report. A small and shrinking spread means the air is close to saturation and fog or low stratus is likely — a spread under about 3 °C on a clear, calm evening is the classic radiation fog setup. A temperature near or below freezing with visible moisture is the icing warning.
- 14/09 — a 5 °C spread, no immediate fog concern.
- 09/09 — saturated; if visibility is still good, it is about to stop being good.
- M03/M05 — minus three, dew point minus five: cold enough to matter in cloud.
- A widening spread through the morning is the fog burning off.
Dew point never exceeds temperature. If you read a report where it appears to, you have mis-split the group.
Reading one in ten seconds#
With practice nobody reads a METAR left to right. The operational scan is: pressure setting, wind against the runway, ceiling, visibility, anything unusual in present weather, then the trend. Everything else is context.
- QNH — set the altimeter correctly before anything else.
- Wind — runway in use and the crosswind component.
- Lowest BKN or OVC layer — is there a ceiling, and where?
- Visibility — is the approach you want still legal?
- Present weather — TS, FZRA, +SN and windshear reports change the plan, not just the numbers.
- Trend — is this improving or falling apart within the hour?
Our decoder on the region pages does exactly this scan and prints it in your language. It is a reading aid, not a substitute for reading the raw line yourself.
Frequently asked questions
What does METAR stand for?
It comes from the French météorologique aviation régulière — routine aviation weather observation. It is an observation, not a forecast: it describes measured conditions at an aerodrome at a stated time, normally issued every half hour or every hour. When conditions change significantly between routine issues, a SPECI is put out in the same format.
How do I decode a METAR quickly?
Read it in the order the groups appear, because the order never changes: station, day and time in UTC, wind, visibility, present weather, cloud from the lowest layer up, temperature and dew point, pressure, then the trend. Anything missing simply means there was nothing to report. In practice most people scan rather than read — pressure setting, wind, ceiling, visibility, present weather, trend — which takes about ten seconds once the groups are familiar.
What does 9999 mean in a METAR?
Visibility of 10 kilometres or more. Visibility is reported in metres in four digits, so 0800 is 800 metres and 4000 is 4 kilometres; 9999 is the top of the scale rather than a literal 9,999 metres. North American reports use statute miles instead, written as 10SM or 1 1/2SM, and CAVOK replaces both the visibility and cloud groups when visibility is 10 km or more with no significant cloud or weather.
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