METAR Wind Decoder
A METAR encodes wind as five digits followed by KT, where the first three digits are direction and the last two are speed.
Wind group: 27018G26KTKJFK at 121851Z
Take 270° at 26 knots to the crosswind component calculator and enter it against your runway heading.
METAR winds are true; subtract local magnetic variation before comparing with a runway number.
Anatomy of a METAR Wind Group
The wind group is fixed-width and positional, so each character can be read by where it sits rather than by any separator: three of direction, two of speed, an optional gust, then the unit.
Variable Directions and Gust Notation
A gust is reported when the peak exceeds the sustained speed by 10 knots or more, and a variable group is added when the direction swings through 60 degrees or more while the wind is above 6 knots.
The gust letter sits inside the wind group itself: 18012G22KT is 180 degrees at 12 knots gusting 22. That 10-knot spread is the reporting threshold, so smaller fluctuations are simply absorbed into the sustained figure and never appear. For planning, the gust value is the number that matters, the aircraft has to handle the peak, not the average, and half the gust factor is conventionally added to the approach speed.
The variable group is separate and follows the wind group: 18012G22KT 150V210 means the same wind swung between 150 and 210 degrees. Both endpoints deserve a crosswind calculation, because the difference across a 60-degree arc is substantial. A wind that varies from 150 to 210 against runway 18 gives anywhere from zero to about 6 knots of crosswind at 12 knots sustained, and the prudent plan uses the worse end.
Below 6 knots the direction is often too unsteady to average at all, and the report substitutes VRB for the three direction digits. There is no meaningful crosswind calculation for a VRB wind; at those speeds no runway presents a control problem, and the value of the report is telling you the wind is not worth planning around.
METAR, TAF, and ATIS Compared
The three sources answer different questions, and only the ATIS gives wind already referenced to magnetic north, the other two need variation applied before they can be compared with a runway number.
METAR
ObservationWhat the weather actually is, measured at the field and issued hourly with corrections in between. Wind is a two-minute average from one sensor, referenced to true north. This is the source to trust for a decision you are making right now.
TAF
ForecastWhat the weather is expected to do, covering a 24 or 30 hour window in blocks. Wind is also true-referenced. A TAF answers whether the crosswind will still be flyable when you arrive, which a METAR cannot.
ATIS
BroadcastA recorded summary for arriving and departing traffic, updated hourly or on significant change. The wind on an ATIS is given in magnetic degrees, so it can be compared with a runway number without converting anything.
For a departure an hour away, the TAF governs. For a decision on the ramp, the METAR is the best written source. On approach, the ATIS is both the freshest and the only one already in the units the runway is labelled in. Once you have a direction and speed, take them to the runway wind component tool to see what the runway actually faces, use the runway comparison tool if the field has more than one option, and see the upper wind forecast guide for the en-route picture. Wind you intend to use for navigation rather than landing feeds the drift correction calculator instead.
METAR Wind Questions
What does VRB mean in a METAR?
VRB replaces the three direction digits when the wind is too variable to report a single direction, which is normally only used at speeds below 6 knots. A report of VRB04KT means the wind is 4 knots from a direction that keeps changing. Above 6 knots a varying wind is instead reported with a mean direction plus a variable group showing the arc it swung through.
How do I know if METAR wind is true or magnetic?
METAR wind is always referenced to true north, without exception. Every written product, METAR, TAF, and winds aloft, uses true. Spoken products intended for immediate runway use, meaning ATIS and tower-reported wind, are magnetic. The rule is easy to remember once framed that way: if you read it, it is true; if you hear it, it is magnetic.
What's the difference between METAR and SPECI?
A METAR is the routine scheduled observation, normally issued once an hour. A SPECI is an unscheduled special observation issued when conditions change significantly between those hours, a wind shift of 45 degrees or more with speeds above 10 knots, a visibility change through a reporting threshold, or the onset of thunderstorms. Both use identical encoding, so anything that reads a METAR reads a SPECI.
Does calm wind get reported differently in METAR?
Yes. Calm wind is encoded as 00000KT, five zeros followed by the unit, rather than being omitted. It means the wind is below the reporting threshold, which in the United States is under three knots. Because the direction digits are zeros rather than a real bearing, no runway has a crosswind and any calculator fed this group should return zero across the board.
How current is METAR wind data?
The observation timestamp sits right after the station identifier, in the form 121851Z, the 12th day at 1851 Zulu. Routine reports are issued near the end of each hour, so a METAR can be up to an hour old before the next one appears. In fast-changing conditions that is long enough for the wind to shift substantially, which is why a SPECI exists and why the ATIS is the better source once you are close to the field.