Climate change will affect stream ecosystems directly, indirectly, and through interactions with other stressors. Biological responses to these changes include altered community composition, interactions, and functions. Effects will vary regionally and present heretofore unaccounted influences on biomonitoring, which water-quality agencies use to assess the status and health of ecosystems as required by the Clean Water Act. Biomonitoring, which uses biological indicators and metrics to assess ecosystem condition, is anchored in comparison to regionally established reference benchmarks of ecological condition. Climate change will affect responses and interpretation of these indicators and metrics at both reference and nonreference sites and, therefore, has the potential to confound the diagnosis of ecological condition. This report analyzes four regionally distributed state biomonitoring data sets to inform on how biological indicators respond to the effects of climate change, what climate-specific indicators may be available to detect effects, how well current sampling detects climate-driven changes, and how program designs can continue to detect impairment. Results can be used to identify methods that assist with detecting climate-related effects and highlight steps that can be taken to ensure that programs continue to meet resource protection goals.