How to Read a METAR: The Aviation Weather Report, Group by Group

A METAR is an airfield's routine weather report. The name is short for Meteorological Aerodrome Report. Larger airfields issue a new one every 30 or 60 minutes, plus a special report called SPECI when the weather changes suddenly. At first glance it looks like a jumble of letters and numbers. The groups always come in the same order, though, and once you know that order you can read a METAR in a few seconds.

Decode a METAR

The decoder already holds an example report. Hover over a group to see what it means. Type an ICAO identifier such as EGLL and it fetches that airfield's current report, or paste a complete METAR. The decoder also has its own page.

An example

We made up the report in the decoder for Leipzig/Halle. It's what a quiet afternoon could look like:

METAR EDDP 291150Z 24012KT 9999 FEW030 BKN045 17/09 Q1016 NOSIG

On the METARMAP, Leipzig/Halle would glow green for this, in the Oscar category. The reason comes further down.

The groups one by one

Station and time

The airfield appears as a four-letter ICAO code. German airfields start with ED, such as EDDM for Munich or EDDH for Hamburg. Day and time follow, always in UTC, which the Z marks. AUTO after it means the report comes from an automatic station with no observer.

Wind

24012KT means wind from 240 degrees at 12 knots. The direction is where the wind blows from, relative to true north. Gusts follow a G, so 24012G25KT means gusts up to 25 knots. VRB03KT is light wind from varying directions and 00000KT is calm. If the direction swings a lot, a separate group such as 210V270 follows.

Visibility

Visibility is given in metres. 9999 is the highest value and means 10 km or more, while 0800 is 800 metres. Airfields with an instrument landing system may add the runway visual range, for example R26/0600 for 600 metres on runway 26.

Weather

Weather is written as abbreviations that can be combined. A minus in front means light and a plus means heavy, so -SHRA is light rain showers and +TSRA is a thunderstorm with heavy rain.

Cloud

Each cloud layer is the coverage in eighths plus the height in hundreds of feet above the airfield. BKN045 is a broken layer at 4500 ft.

CB or TCU attached to a layer means cumulonimbus or towering cumulus. VV002 is a vertical visibility of 200 ft, used when fog or something similar hides the sky. NSC means no significant cloud.

For flight planning the cloud ceiling matters most. It's the lowest layer reported as BKN or OVC. In the example it's at 4500 ft, and the FEW clouds at 3000 ft don't count.

Temperature and dew point

17/09 means an air temperature of 17 °C and a dew point of 9 °C. Below zero is written with an M, so M02 is minus 2 °C. When the two values are close, the air is very humid, and fog or low cloud becomes more likely.

Pressure

Q1016 is the QNH in hectopascals, the air pressure converted to sea level. Pilots set their altimeter to this value. In the US you'll see an A with inches of mercury instead, for example A2992.

Trend

Many airfields end the report with a forecast for the next two hours. NOSIG means no significant change is expected. BECMG announces a lasting change and TEMPO a temporary one.

CAVOK

Sometimes visibility, weather and cloud are replaced by CAVOK, short for Ceiling and Visibility OK. It means at least 10 km visibility, no cloud below 5000 ft or the highest minimum sector altitude, no cumulonimbus or towering cumulus and no significant weather.

Two more examples

These reports are made up as well. First, a foggy morning:

METAR EDDP 290650Z 00000KT 0800 FG VV002 08/08 Q1021 BECMG 3000 BR

No wind, 800 metres visibility, fog and a vertical visibility of 200 ft. Temperature and dew point are equal, so the air is saturated. The trend says the fog should thin to mist with 3000 metres visibility within two hours. On the METARMAP the airfield glows red, in the X-Ray category.

Then a thundery afternoon:

METAR EDDP 291520Z 27018G32KT 6000 TSRA BKN025CB 22/17 Q1009 TEMPO 3000 +TSRA

Wind from 270 degrees at 18 knots with gusts up to 32 knots, 6 km visibility, a thunderstorm with rain and a broken layer with cumulonimbus at 2500 ft. Heavy thundery rain with 3 km visibility is expected at times. Visibility and ceiling put this in Delta, so the LED glows yellow. Because the wind is above the default limit of 15 knots, it blinks as well.

From METAR to colour

The METARMAP takes the visibility and the cloud ceiling from each METAR and assigns one of the five GAFOR categories. In the first example that's more than 10 km visibility and a ceiling at 4500 ft. Charlie would need another 500 ft, so the result is Oscar. Our article on GAFOR colours explains exactly where the limits lie.

Frequently asked questions