I understand that METARs report wind direction as true and ATIS reports it as magnetic. But at Camarillo (KCMA) both are reporting the same wind direction and speed even though the magnetic variation is 12.5 degrees. Why does the written versus spoken rule not apply here?
For the US
From the FAA ATC manual:
NOTE− [...] The ASOS Operator Interface Device (OID) displays the magnetic wind as “MAG WND” in the auxiliary data location in the lower left−hand portion of the screen. Other OID displayed winds are true and are not to be used for operational purposes.
Which confirms the ATIS winds are magnetic.
I just listened to KCMA ATIS, the wind reported is 10 degrees more than the METAR.
It's not the same.
Both METAR and ATIS report mean wind information, for the direction, both report in true heading. ATC report is magnetic.
ATIS wind velocity is latest two minute average. The wind direction broadcast is given in degrees true.
ATC plain language ad hoc wind directions given during final approach or just prior to or during the take off roll are likely to be given in degrees magnetic.
Here’s the info for ASOS.
ASOS computer-generated voice message are made available through telephone dial-in access and are broadcast directly to pilots via ground-to-air radio (where installed). The information contained in the ground-to-air radio broadcast message and the telephone dial-in message are identical. The voice message is composed of the body of the ASOS observation and selected remarks. Selected remarks can include variable visibility, tower visibility, or Density Altitude when 1,000 or more feet above airport elevation. Control tower personnel may add Notice to Airmen (NOTAM) or other information. Note that wind direction in the voice message is given in degrees magnetic.