Temperature is a critical component of freshwater ecosystems, influencing a wide range of phenomena from phenology of individuals to interactions within aquatic communities. This symposium brought together empirical data, statistical tools, and mechanistic models describing thermal regimes in aquatic systems, with the intent of determining which techniques are best equipped for understanding these regimes and the role of natural and human disturbance in altering or maintaining them. Presenters exhibited the power of large collaborative datasets, customized air and water temperature monitoring programs, airborne infrared imaging, process-based hydrology/temperature models, and spatial stream network models. Each method provided a somewhat different perspective on how to overcome the challenge of high levels of spatial and temporal variance in aquatic thermal regimes in order to make predictions of future thermal regimes and identify best management strategies for thermal habitats and dependent freshwater species. Strategic data collection, analyses that incorporate covariation in water temperature patterns over space and time, and research on the impact of human disturbances like wildfire, dams, and climate change on biologically relevant aspects of thermal regimes emerged as high priorities for the future. — Elliot Koontz, UW (QERM), [email protected] Read the symposium abstracts here.