Coldwater stream habitats are vulnerable to effects of climate change, particularly to changes in precipitation and air temperatures that alter their hydrology. Some of these streams are expected to diminish in size, permanently transition to warmer habitats, or possibly go dry. However, streams in deep canyons, poleward-facing slopes, thick canopy cover, groundwater-fed areas, and with fewer anthropogenic impacts are more likely to resist these changing conditions. Such areas may act as coldwater refugia—areas buffered from climate change that enable persistence of the ecosystem and its resources—and may provide long-term habitat to ecologically and economically important species.