CLIMAS, the Climate Assessment Project for the Southwest, was established in 1998 with seed funding from the National Oceanic and Atmospheric Administration (NOAA) to assess climate variability and longer-term climate change in terms of impacts on human and natural systems in the Southwest. The project's mission is to improve the ability of the region to respond sufficiently and appropriately to climatic events and climate changes. CLIMAS aims to foster participatory, iterative research involving researchers, decision makers, resource users, educators, and others who need more and better information about climate and its impacts. In support of these efforts, the project fosters research on the nature, causes, and consequences of climate change and variability in the Southwestern U.S., and supports efforts to improve climate and hydrologic forecasting in the region. CLIMAS is part of a larger initiative to develop better-quality and more-detailed climate assessments at the regional level. To this end, the project, which is housed within the Institute for the Study of Planet Earth at the University of Arizona, supports interdisciplinary research on past, current, and future climates in the region and provides a focal point for identifying and serving the information needs of stakeholders at the local, state, national, and international levels. CLIMAS brings together researchers who study the processes and effects of climate on the Southwest region with individuals and organizations who need climate information to make informed decisions. The initial focus of CLIMAS is on: i) working with stakeholders to identify and evaluate climate information and forecast needs and products, ii) supporting research on physical characteristics and processes, iii) supporting research on human and ecological impacts, iv) providing Southwest climate information and forecasts to people in the public, private, and non-profit sectors, and v) participating in climate assessment activities carried out in other regions and by various governmental entities.