CLIMAS, established in 1998, is the Regional Integrated Sciences and Assessments program in the Southwest. The primary geographic focus of the program is Arizona and New Mexico, although members of the CLIMAS team conduct research around the world. Headquartered at the University of Arizona’s Institute of the Environment, CLIMAS also includes a core group of investigators at New Mexico State University as well as affiliated researchers throughout the West. The CLIMAS mission is to improve the region’s ability to respond sufficiently and appropriately to climatic events and changes. The program promotes participatory, iterative research involving scientists, decision makers, resource managers, educators, and others who need more and better information about climate and its impacts. CLIMAS investigators conduct research on the nature, causes, and consequences of climate change and variability in the southwestern United States, providing valuable information to decision makers in a variety of fields, including water and fire management, agriculture, ranching, and public health. The program also supports efforts to improve climate forecasting in the region. Since its establishment, CLIMAS has built a large, diverse network of stakeholders and partners who have worked together on a tremendous range of projects.