METAR Wind Decoder – Aviation Weather Wind Guide

METAR stands for Meteorological Aerodrome Report. It is the standard format airports use to report current weather, and pilots around the world read the same coded line no matter which country they fly in. ICAO Annex 3 sets the format, and the FAA adopts it for every controlled airport in the United States.

A routine METAR comes out once an hour, usually a few minutes before the hour. It packs a lot into one line: station identifier, day and time in Zulu, wind direction and speed, visibility, cloud layers, temperature, dew point, and altimeter setting. Pilots read the wind group first when planning a takeoff or landing, since it decides which runway to use and how much crosswind to expect.

Not every METAR waits for the clock. When weather changes fast, airports issue a SPECI (special report) between the hourly cycle. A wind shift of 30° or more, a sudden gust, or visibility dropping below a set threshold can all trigger a SPECI. For crosswind planning, always check whether a SPECI has been issued since the last routine METAR. It can carry a very different wind reading than the one you last briefed.

METAR wind uses the format DDDffKT: three digits for direction, two (or three) digits for speed, then the letters KT for knots. Read 27020KT as wind from 270° at 20 kt. Read 09005KT as wind from 090° at 5 kt.

Direction is always the compass bearing the wind is blowing from, not toward. A report of 36010KT means the wind comes out of the north at 10 kt, so an aircraft taking off toward the north faces a headwind, not a tailwind.

Speed almost always comes as two digits. Once wind speed reaches 100 kt, rare outside of hurricanes and severe storms, the group switches to three digits. KT marks knots; a handful of countries in the former Soviet Union use MPS (metres per second) instead, so always check the units before running a crosswind calculation.

Calm wind gets its own code: 00000KT. When the airport records no measurable wind, direction and speed both read zero, and there is no crosswind or headwind to compute. In that case any runway works equally well from a wind standpoint, and pilots choose based on traffic pattern, noise abatement, or taxi distance instead.

Gusts append a G and the peak speed right after the steady wind: 27020G35KT means wind from 270° at 20 kt, gusting to 35 kt. ICAO reporting practice adds a gust value whenever peak speed exceeds the mean speed by 10 kt or more within the past 10 minutes.

The 15-knot difference between steady and gust speed in that example is the gust factor, and it matters for planning. A steady 20-knot crosswind might sit comfortably under your aircraft's demonstrated limit, but a 35-knot gust could push the same crosswind component well past it.

For runway and go/no-go decisions, run the crosswind calculation twice: once with the steady speed and once with the gust speed. Plan around the gust number, not the average. A landing that looks fine on paper with the mean wind can turn into a full-deflection fight for control the moment a 15-knot gust hits on short final.

VRB replaces the three-digit direction when wind direction shifts too fast to pin to one heading, as in VRB03KT. METAR only uses VRB at low speeds, generally under 6 kt, since a fast-moving wind that varies that much is unusual.

At higher speeds, direction can still wander without qualifying for VRB. When it swings 60° or more during the 10-minute observation window, the METAR adds a variability range right after the wind group: 27020KT 240V310 means wind from 270° at 20 kt, oscillating between 240° and 310°. Run the crosswind numbers at both extremes and plan for the worse of the two.

METAR reports what the wind is doing right now, timestamped to the minute it was observed. TAF (Terminal Aerodrome Forecast) predicts what the wind will do later, usually covering the next 24 to 30 hours in blocks.

Use the latest METAR for any decision happening in the next few minutes: taxi, takeoff, or an arrival that is minutes out. Use the TAF when you are still hours from landing and need to judge whether the crosswind will stay within limits by the time you arrive. As your ETA gets closer, switch back to the METAR, and check it against the TAF for any FM (from) or BECMG (becoming) wind change groups.

Turning a METAR into a crosswind number takes four steps.

Step 1: find the wind group and pull out DDD (direction) and ff (speed). In 24015G22KT, direction is 240 and speed is 15, gusting 22.

Step 2: note the runway you plan to use, converted to a heading. Runway 27 points to roughly 270°.

Step 3: enter the wind direction, wind speed, and runway heading into the crosswind calculator. It runs XWC = V × sin(θ) and HWC = V × cos(θ) automatically.

Step 4: read XWC (crosswind component) and HWC (headwind or tailwind component) off the result, and check both the steady and gust figures against your aircraft's demonstrated crosswind.

The METAR decoder above skips the manual steps: paste the raw METAR text, pick your runway, and it extracts direction, speed and gust, then feeds them straight into the same crosswind formula.

METAR is not the only place wind numbers come from. ATIS (Automatic Terminal Information Service) broadcasts a live, spoken paraphrase of the current wind at towered airports, updated as conditions change rather than once an hour. It often reflects a fresher wind reading than the last published METAR, especially in gusty conditions, so cross-check both if either looks off.

Behind every METAR sits a network of physical sensors. In the United States, NOAA runs the underlying observation network that feeds airport weather stations, and national meteorological offices do the same job in other countries. The METAR is just the formatted summary of that raw sensor data.

Watch the trend between two consecutive METARs, not just the latest one. A rapid wind shift, say from 180° at 8 kt to 250° at 22 kt gusting 30 within one hour, can signal an approaching gust front or wind shear well before the next TAF update mentions it. If the last two METARs disagree sharply, treat the newer one as the more urgent warning and expect more change on the way.