METAR Guide: Everything in a Surface Weather Report
A METAR packs a full surface weather observation into about two lines. This METAR guide walks through the whole report in the order it is written, and points at the page that covers each part in detail.
Read it once end to end and the format stops being a wall of capitals. The order never changes, which is what makes it learnable.
What a METAR is
A METAR is an observation, not a forecast. It records what the weather did at one airport, at one minute.
Most stations issue one every hour, near the end of the hour. When conditions change sharply between those times, the station sends a SPECI instead, which is an unscheduled special report decoded exactly the same way.
That difference matters more than it sounds. It is the whole reason a TAF exists alongside it.
The order of the groups
Every METAR follows the same sequence, and nothing is ever reordered.
Report type comes first, then the station identifier, then the date and time in
Zulu. Then any modifiers such as AUTO or COR.
Then the body: wind, visibility, present weather, sky condition, temperature and dew point, and the altimeter.
Then RMK, and everything after it is a remark.
Groups can be absent. A dry, clear, calm day drops the weather group entirely. Nothing shifts along to fill the gap, so a missing group tells you something.
Wind and visibility
The wind group gives direction, speed and gusts in one block. 21016G24KT is
from 210 degrees at 16 knots, gusting 24.
Two variants come up often. VRB marks a
variable direction, used when the wind is light
and swinging. 00000KT is calm.
Visibility in the US is statute miles, so 10SM is ten miles. Elsewhere it is
metres, where 9999 means ten kilometres or more.
When visibility is poor, RVR groups give the measured range down a specific runway, and those are the numbers that drive approach minimums.
Sky condition and the ceiling
Cloud is reported by cover and height, in layers from the lowest upward.
Cover runs FEW, SCT, BKN and OVC, measured in eighths of the sky. Height
is in hundreds of feet above the field, so BKN015 is a broken layer at 1500
feet.
The ceiling is the lowest BKN, OVC or
VV layer. FEW and SCT are never ceilings, however low they sit.
When the sky is blocked out altogether, a
vertical visibility group such as VV002
replaces the cloud layers and gives how far up you can see.
Flight categories
The category is a one-word summary drawn from just two numbers: the ceiling and the visibility.
Each is checked separately and the worse of the two decides the result. A field with a 5000 foot ceiling and one mile visibility is IFR on the visibility alone.
If there is no ceiling at all, the category comes from visibility by itself. The exact thresholds for VFR, MVFR, IFR and LIFR are on the flight categories page.
Remarks
Everything after RMK adds detail the body has no room for, and US stations use
this section heavily.
Sea-level pressure, temperature to a tenth of a degree, hourly precipitation and
pressure tendency all live here. So do
automated station flags such as AO1 and AO2,
which say what the sensors can and cannot detect.
Remarks are also where a human observer adds what the machines missed. At an automated field with no augmentation, a thunderstorm beside the runway may appear nowhere in the report.
Automated and human reports
Who made the report changes how much it can tell you, and one code says which.
AUTO means no human was involved. The sensors did all of it. Most US stations
run this way for most of the day.
That matters because a machine has blind spots. The cloud sensor looks straight up, so cloud that never crosses it is never reported. The visibility sensor reads one point, not the whole horizon. Storms are found by lightning detectors, so a storm with no detected strike may not appear.
A human observer catches all three. So a report with AUTO and no added remarks
means nobody was outside looking.
Read the flags before you trust a quiet report from a field you do not know.
Verdict on this METAR guide
Work through a METAR in the order it is written and it decodes cleanly every time. Type, station, time, modifiers, then wind through altimeter, then remarks.
Two habits do most of the work. Find the ceiling by looking only at BKN, OVC
and VV, and take the worse of ceiling and visibility for the category. For any
single group, the full abbreviation list has the
code and the page that explains it.
Frequently asked questions
What does METAR stand for?
Meteorological Aerodrome Report. It is a routine surface weather observation from an airport, encoded in a compact international format, and most stations issue one every hour near the end of the hour.
How often is a METAR issued?
Usually hourly, around 53 to 55 minutes past. When conditions change sharply between routine reports, the station issues a SPECI instead, which is an unscheduled special report read exactly the same way.
What order do the groups come in?
Type, station, time, modifiers, wind, visibility, weather, sky condition, temperature and dew point, altimeter, then RMK and the remarks. The order never varies, so a missing group is information rather than an error.
How do I work out the flight category?
From the ceiling and the visibility, taking whichever is worse. The ceiling is the lowest broken, overcast or vertical visibility layer. FEW and SCT layers are never ceilings.
Is a METAR the same everywhere in the world?
The body follows one international standard, so wind and cloud codes read the same anywhere. Units differ: the US uses statute miles and inches of mercury, most of the world uses metres and hectopascals.