http://www.ga.gov.au/oracle/geomag/agrfform.jsp
Australian Geomagnetic Reference Field Computation
Requested: Latitude
-16o 55' 00", Longitude
145o 46' 00", Elevation
0 km, Date
2012/11/14
Calculated: Latitude
-16.9167o, Longitude
+145.7667o, Elevation
0.00 km, Epoch
2012.8689
Magnetic Field Components
D = 6.909 deg
dD = -0.026 deg/yr
That lat/lon is Cairns North.