Values of persistence of precipitation for each of the four seasons have been derived for 108 cities in the conterminous United States for a selected combination of time intervals. These values show significant differences between stations and seasons and shed considerable light on the general behavior of storm systems and atmospheric circulations responsible for precipitation occurrences. Examples are given illustrating the application of persistence to the forecasting problem, and the relationship between persistence and the coefficient of correlation involving successive precipitation events is developed. The data presented should serve as important supplementary information to the forecaster in evaluating continuity trends in precipitation.

Climate change poses many challenges that affect society and the natural world. With these challenges, however, come opportunities to respond. By taking steps to adapt to and mitigate climate change, the risks to society and the impacts of continued climate change can be lessened. The National Climate Assessment, coordinated by the U.S. Global Change Research Program, is a mandated report intended to inform response decisions. Required to be developed every four years, these reports provide the most comprehensive and up-to-date evaluation of climate change impacts available for the United States, making them a unique and important climate change document. The draft Fourth National Climate Assessment (NCA4) report reviewed here addresses a wide range of topics of high importance to the United States and society more broadly, extending from human health and community well-being, to the built environment, to businesses and economies, to ecosystems and natural resources. This report evaluates the draft NCA4 to determine if it meets the requirements of the federal mandate, whether it provides accurate information grounded in the scientific literature, and whether it effectively communicates climate science, impacts, and responses for general audiences including the public, decision makers, and other stakeholders.