A new master plan for the historic city of Bet She'an opens the opportunity for climatic design on an urban scale. Bet She'an is one of the oldest cities in the Middle East, with archeological layers dating from 1900 bc. Egyptians, early Israelites, Greeks, Romans, Byzantines, early Moslems, Crusaders, Ottomans and more recently British and Israelis were dominant cultures that lived in Bet She'an. Each used a unique strategy to adapt the built environment to the harsh climatic conditions which exist at the margin of the very hot, arid Jordan Valley, which is the lowest part of the known Syro-African Rift Valley. Despite an impressive history of climatic adaptations, the last two generations have not effectively utilized the experience of previous inhabitants. One of the aims of the master plan is to reintegrate the climatic design at all levels, renew the historic features and thereby improve the climatic quality. Analysis of climatic data served as a starting point for the identification of planning problems. The master plan solutions are presented on 3 scales: 1. (1) overall urban scale; 2. (2) neighborhood scale, and 3. (3) individual building scale. It is the scope of this study to present the climatic rehabilitation of an ancient city as part of a process for the general understanding of our history and environments and to create guidelines for future climatic rehabilitations of cities.