|Rockefeller Center - NYC|
(FEB-69 AO: -1.325; MAR-69 AO: -2.084)
The last time the March AO went below -1 was in 2006.
The last time the March AO tanked below -2 was in 1984.
The AO for the preceding meteorological winter (D-J-F) averaged -1.122.
The AO/s 5-year moving average during meteorological winter is -0.909
The AO during meteorological winter has been negative...
....four of the last five seasons (average = -0.413)
...nine of the last 10 seasons (average = -0.368)
...12 of the last 15 seasons (average = -0.255)
Not that any of these trends are abnormal.
The 5-year moving average was negative during the vast majority of the time between mid-50s to late '80s. The abnormal 'positive ' period occurred between 1989 and 1996.
Monthly AO data here.