The sub-tropical ridge (STR) over Australia divides climate dominated by the zonal west winds and associated winter rainfall, to the south, from tropical conditions, dominated by EN-SO, to the north. Historical data, summarised by Das (1956), suggest that the annual mean latitude of the STR over eastern Australia has been shifting polewards since the early 1900s. To examine this trend in greater detail, I up-dated the historical data by determining the daily mean position of maximum sea level pressure along the 150º E. longitude (Pittock’s L) since 1967, and then compiling these into monthly, seasonal and annual means. The consequent values for annual mean L, determined from the SLP charts, are almost identical to those calculated by Pittock through 1972 from instrumental records, and are similar to those published for 1988 to 1993 in the Climate Monitoring Bulletin Australia (BOM). The recent data indicate, first, that the STR has shifted nearly 5 latitude degrees to the south since the early 1900s, and second, that the date on which its reaches its winter minimum latitude has been delayed by nearly three months since the 1960s. The rate of change was greatest in the 1970s, which suggests the changes are related to the contraction of the Antarctic polar vortex and the delay in its annual breakdown. However, the correlation with Antarctic indices is not compelling, suggesting that both the latitude of the STR and the Antarctic variability are parallel responses to a common underlying climate variable. Perhaps reflecting this, both the annual mean latitude of the STR and its seasonal delay correlate highly with global stratospheric ozone levels, suggesting a direct impact of the latter on mid-latitude tropospheric climate. The effects of the poleward shift and delay of the STR appear to affect variables as diverse as rainfall over temperate Australia, the strength of western boundary currents in the Tasman Sea, deep-ocean temperatures and biology, and the viability of marine populations and industries in southeastern Australia.