METAR READER

HOW TO DECODE A METAR

Here is an example of a North American METAR:

METAR CYOW 110400Z 34008G15KT 15SM -FZRN FEW022 OVC060 03/M01 A3008 RMK SLP194=

Going through piece by piece:

METAR

This identifies that the radio signal is a METAR, or Meteorological Terminal Aviation Routine Weather Report.

CYOW

This identifies the 4-letter code of the station or airport that transmitted the report.

Airport codes are designated by ICAO (International Civil Aviation Authority).

This code is for the Ottawa Macdonald–Cartier International Airport in Ottawa, Canada.

110400Z

Timestamp in UTC. the first two numbers represent the date of transmission (the 11th of that month).

0400 means it was transmitted at 04:40 in 24-hours time.

The 'Z' conveys that the time is givin in ZULU, or aviation speak for UTC.

34008G15KT

Wind information section. First three numbers represent wind dirrection, in this case 340 degrees true.

Next section represents wind speed, with the 'KT' meaning knots. The first two numbers represent normal wind speed, while the numbers aftern the G represent gusts.

In this case, the wind is 8 knots gusting to 15 knots.

15SM

States the visbility at ground level in statute miles. In this case the visibility is 15 miles.

-FZRN

This section shows predominant weather. Weather is represented by two or four letter long codes.

In this case, 'RN' means rain, 'FZ' is a qualifeir meaning freezing, so the predominant weather is freezing rain.

The '-' symbol tells pilots that the weather is light, while '+' would mean heavy.

Here is a table of common weather codes:

FEW022 OVC060

This sections shows cloud cover.

There are 5 levels of cloud cover: Clear sky(SKC or CLR), scattered (SCT), broken(BKN), and overcast (OVC).

Cloud cover varries by altitude, so the last three numbers state cloud cover altitude in units of 100 feet.

So at this airport, there are few clouds at 2200 ft, while it is overcast at 6000 ft.

03/M01

This is the tempreture reading. The first section before the slash is the current tempreture in degrees celcius.

The second number represents the current dewpoint. The 'M' before the number signifies that the readings are below 0.

In this case, the tempreture is 3°C, while the dewpoint is -1°C.

A3008

This number shows the recommended altimeter calibration setting in inches of mercury.

In this case, altimeters should be set to 30.08 "Hg.

RMK SLP194=

This section is for extra remarks.

In this case, the remark is that the pressure at sea level (SLP) is 194 hPa (even).