Winter '12 / '13 - Arctic Oscillation - Meteorological Winter - Day One

Not sure it means anything but here's the state of the AO during its 63-year period of record on the first day of meteorological winter.



BLUE line is the observed AO index on 01-DEC.
RED line is the 9-point binomial filter.  The filter removes noise from the signal to highlight the trend.

The DEC-12 AO is the third lowest on record behind DEC-85 (-3.783) and DEC-97 (-2.603).



Same idea for AO/s sister...the North Atlantic Oscillation (NAO).