A method for studying patterns of inter-annual variability arising from intra-seasonal variability has been applied to the extratropical wintertime 500hPa geopotential height in the Southern Hemisphere, using data from the NCEP-NCAR reanalysis and a long integration of the Australian Bureau of Meteorology Atmospheric Model (BAM). In particular, the method, using monthly mean data, provides estimates of the inter-annual variance and covariance, in the seasonal mean field, which arise from intra-seasonal variability. These estimates can be used to derive patterns of inter-annual variability associated, therefore, with physical processes that vary significantly within a season, such as, for example, atmospheric blocking, or intra-seasonal oscillations. Removing this intra-seasonal component of inter-annual variability from the total inter-annual variance/covariance, derived from the seasonal mean field, one can define a "residual" component of inter- annual variability. This latter component is more closely related to external forcings and very slowly varying (inter-annual/supra-annual) internal dynamics. The patterns associated with this component are related to well known Southern Hemisphere teleconnections.