Observations of Antarctic polar stratospheric clouds (PSCs) were examined using the 1-μm aerosol extinction ratio data from the SAM II satellite experiment for the years 1979--1982 and 1984--1987. PSCs were sighted between 10 and 25 km and were usually first observed by mid-June. Clouds disappeared earlier at higher altitudes (late August near 24 km, in most cases) and later at lower altitudes (late September or October near 16 km). It was found that PSCs persisted longer in 1985 and 1987 at 18 km and were more frequently observed in September and October 1987 than the other years. Inference of likely PCS formation regions from National Meterological Center temperature data indicated that clouds would begin forming in late May and usually disappear in September. This analysis confirmed the persistence of colder conditions during the spring of 1987. ¿ American Geophysical Union 1989