Weather station reports. True or magnetic

[ivo]

Question to all wind gurus here

Weather stations wmo and madis report their wind direction in true or magnetic?

[GiovanniV]

Wind direction is defined as the direction from which the wind blows, and is measured clockwise from geographical north, namely, true north (based on the World Geodetic System 1984 (WGS-84) and its Earth Geodetic Model 1996 (EGM96)). - source: WMO

[ivo]

Even in METARs? I guess METARs use magnetic.

[Gkikas LGPZ]

@ivo
I copy from https://www.faa.gov/air_traffic/publications/media/aim.pdf
Chapter 7, section 1

[GiovanniV]

I am not familiar with weather reports in the flight sector but according to German weather service (DWD) it is reported in true north(German source: DWD).

[Gkikas LGPZ]

@ivo
Maybe you refer to:
If you read it (METAR), it's true. If you hear it (ATIS), it's magnetic.

All charts and textual sources (METAR, TAF, winds aloft, surface analysis charts, etc) use true north as the reference.

ATIS/AWOS/ASOS broadcasts, or any information a controller gives you over the radio, is magnetic.

See:International Airport Example 1,
here https://en.wikipedia.org/wiki/Automatic_terminal_information_service

[Gkikas LGPZ]

@ivo
As the magnetic declination in Czech Rep. is 3~5 degrees and wind direction is given in tens of degrees, you have no problem!
But if you fly to Greenland ....
https://screenshots.firefox.com/kCNSJ4D19uIqOUNs/upload.wikimedia.org
the ATC will give you wind dir. (for landing) in magnetic
(also runways names (01 up to 36), refer to magnetic azimuth in tens of degrees).

[robertocosquin]

No problem

[csabatatar]

@ivo
I totally agree with @Gkikas-LGPZ .
The best mnemonic for it is: WRITTEN --> TRUE; SPOKEN --> MAGNETIC.

[regetr]

@ivo

from ICAO annex 3/chapter 4;