In a geographic information system (GIS), suitability analysis is used to model the spatial distribution of suitability within a region of interest with regard to a planning goal. This analysis is based on the combination of multiple geospatial source datasets, which spatially overlap, and each encodes a factor that contributes a certain weight to the overall suitability. “Possibility space” refers to an event space that represents all possible outcomes of the suitability analysis. This paper proposes an interactive possibility space for real-time visualization and exploration with a goal to help understand meaningful relationships between variable combinations and the suitability outcomes. A case study for siting wind farm locations in northwest Iowa is presented to demonstrate the practical application and usefulness of the possibility space.