In 1961 Congress allocated funding for the creation of a weather modification program headed by the Bureau of Reclamation. Project Skywater came fifteen years after Irving Langmuir, Vincent Schaefer, and Bernard Vonnegut of the General Electric Laboratories in Schenectady, New York, successfully demonstrated that "seeding" clouds with nucleating agents like dry ice (carbon dioxide) and silver iodide produced rain. Skywater aimed to demonstrably prove that there was a practical basis for weather modification, as it was popularly called, in terms of cost-benefit and environmental sensibility. Nevertheless, the task was both daunting and singular. The science behind rainmaking was embryonic and not thoroughly tested against the complex variables that govern the weather. Moreover, never before had Reclamation embarked on such a project: a program of taking water management to the skies, of extensive coordination with government and non-government entities typically not involved in surface or ground water issues, of collecting data over a large area, and of understanding a system as large, unwieldy, and unpredictable as the weather.In 1964 a report of the National Academy of Sciences produced by a panel of experts from the scientific community and government agencies gave a grim diagnosis of the changing of weather. The report critiqued "present efforts which emphasize the a posteriori evaluation of largely uncontrolled experiments," and instead proposed "patient investigation of atmospheric processes coupled with exploration of the technological applications." It predicted that even after a very costly and lengthy period of study and testing, not everything could possibly be known about the atmosphere. The program required "integrated large-scale studies" on the structure and dynamics of convective clouds, the physics of precipitation, the initiation of convection in the boundary layer, the effects of cirrus and dust layers on the radiation balance, the dynamics of severe storms, such as thunder- and hailstorms, tornadoes, and hurricanes, and the role of convection therein.Contents: Project Skywater * The History of Rainmaking * Postwar Science and Legislation * The Politics of Project Skywater * Technology, Testing, and Implementation * Conclusions