A varied and growing group of users now require accurate climate projections, particularly high-resolution projections and projections incorporating meteorological and hydrologic extremes, for all manner of impacts, adaptation, and vulnerability assessments. There has recently been explosive growth in the number of regional climate data sets to address these needs, with varied accuracy in different metrics and incomplete validation. However, with little guidance on how to choose among them, a usability gap continues to exist between their production and their use in addressing outstanding questions in climate science. Decision-makers (particularly water managers) often have difficulty using these data sets as well and have called for "actionable science" and "co-production" of science: The core idea being that stakeholders and scientists should be engaged in a two-way exchange about each others' needs and capabilities. These circumstances have arisen largely because no standardized procedure exists for validating regional climate datasets and communicating their associated credibility information. To address this need, our project proposes a series of seven tasks that will build a stakeholder-driven assessment capability, explain why certain biases arise in regional climate modeling systems, and better understand human impacts on the climate system.