A speleothem isotopic record taken from Jerusalem is used to reconstruct regional climate over the last 170,000 years. Glacial periods in Jerusalem were generally cooler and wetter than the present climate. Stage 5e in the desert margin of Jerusalem was extremely unstable, dry, and warm, and instability persisted throughout the transition to glacial conditions. The climate after stage 5e became gradually cooler and wetter over a 20,000-year interval and did not recover to interglacial conditions in stages 5c and 5a. The Δ 13C varied by up to 12?, from glacial (stages 6, 4, 3, 2) values of -10 to -12? that reflect dense C3 vegetation above the studied cave, and up to 0? in early stage 5 when there was probably complete loss of vegetation. The climatic instability during interglacial periods is much larger than during glacial periods, and glacial/interglacial transitions do not behave the same in each climatic cycle in this region. ¿ 2000 American Geophysical Union