Changes in the hydrological cycle remain one of the least certain aspects of future climate projections. Simultaneously, the paleoclimatic record over the Cenozoic, the last 65 million years, of Earth history offers several examples of global climate change that resulted in dramatic reorganizations of the global and regional hydrological cycle. Records from these past climates, each with varying greenhouse gas levels, can shed light on processes relevant for understanding future hydroclimate. These climates include Last Glacial Maximum, the mid-Pliocene, the Paleocene-Eocene Thermal Maximum, and other time intervals. This session seeks contributions that use data and insights from past Cenozoic climates to enhance our physical understanding of the ways in which the hydrological cycle, including components such as precipitation, evaporation, lake level, soil moisture, respond to climate change. We welcome contributions from proxy record development and modeling experiments or new theoretical frameworks, as well as studies that integrate these two approaches.