Regional characteristics of the seasonal variations in the Southern Hemisphere storm tracks are examined on the basis of a reanalysis data set. If the tendency of much stronger near-surface baroclinicity beneath the subpolar jet stream (SPJ) than beneath the subtropical jet stream (STJ) is taken into account, the overall characteristics can be interpreted reasonably well from potential-vorticity perspective of baroclinic eddy growth and the concept of downstream development of a baroclinic wavepacket. In the lower troposphere, storm track activity is modulated spatially and seasonally, in accordance with local baroclinicity near the surface rather than in the lower troposphere. The activity tends to be confined along the SPJ throughout the year, even in austral winter and spring when the STJ develops over the South Pacific. In the upper troposphere, storm track activity at a particular location is strongly influenced by incoming wave activity from upstream, which tends to dominate over the local influence of near-surface baroclinicity. As a result, the seasonal march in eddy amplitude in the core region of the subpolar storm track over the south Indian Ocean is much more modest in the upper troposphere than at the lower levels. When the STJ intensifies in winter and spring, wave activity accumulated in that core region is dispersed mostly equatorward. The dispersed wave activity tends to be trapped by the STJ, which sustains high eddy activity along the upper-tropospheric subtropical storm track over the Pacific despite the lack of strong near-surface baroclinicity. At the same time, the equatorward dispersion leads to the suppression of upper-level eddy activity along the Pacific SPJ, despite the seasonal enhancement in the lower-tropospheric eddy activity and near-surface baroclinicity underneath.