A newly published dataset, developed by the NC CASC in partnership with ClimateToolbox.org, provides detailed projections of the Standardized Precipitation Evapotranspiration Index (SPEI) for the contiguous United States. SPEI is a widely used drought index that captures changes in both precipitation and potential evapotranspiration, making it a robust indicator of water availability under a warming climate. This dataset is based on downscaled climate projections and represents one of the first comprehensive efforts to provide SPEI time series data for future climate scenarios at a high spatial resolution. The data release—Thota, Hegewisch, and Rangwala, 2025—is now publicly available through the US Geological Survey here or a Thredds server here. 

Developed using the University of Colorado’s supercomputing facility to process the large data volume, this SPEI dataset is already being used by resource managers and researchers for planning and adaptation efforts. To make the data more accessible, ClimateToolbox.org has integrated the data into its Future Time Series tool, allowing users to selectively explore, visualize, and download SPEI projections for locations across the U.S. As climate extremes intensify, tools like this help bridge complex climate data with real-world decision-making—offering a crucial resource for those on the frontlines of drought preparedness.