From the mid-1960s to the mid-1970s, the National Academies produced three reports on weather modification which were aimed at guiding future research and policy development. It has been three decades since the last Academies report, and despite more recent assessments by other bodies such as the American Meteorological Society and the World Meteorological Organization, a need was seen for an evaluation of weather modification research and operations in the United States. Thus, the National Academies convened a committee to assess the ability of current and proposed weather modification capabilities to provide beneficial impacts on water resource management and weather hazard mitigation. Specifically, the committee was charged to: (1) review the current state of the sciences of weather modification and the role of weather prediction as it applies to weather modification, paying particular attention to the technological and methodological developments of the last decade; (2) identify the critical uncertainties limiting advances in weather modification science and operation; (3) identify future directions in weather modification research and operations for improving the management of water resources and the reduction in severe weather hazards; and (4) suggest actions to identify the potential impacts of localized weather modification on large-scale weather and climate patterns. The findings and recommendations of this study will be discussed.