Objectives. To determine if and how state and local public health departments present information about climate change on their Web sites, their most public-facing platform.Methods. We collected data from every functioning state (n = 50), county (n = 2090), and city (n = 585) public health department Web site in the United States in 2019 and 2020. We analyzed data for presence and type of climate-related content and to determine whether there existed clear ways to find climate change information. We analyzed Web sites providing original content about climate change for explanatory or attributional language.Results. Fewer than half (40%) of state health department Web sites, and only 1.6% of county and 3.9% of city Web sites, provided clear ways to find climate change information, whether through provision of original content or links to external agencies' Web sites. Among Web sites providing original content, 48% provided no explanation of climate change causes.Conclusions. National and global public health associations have identified climate change as a public health emergency, but most state and local public health departments are not delivering that message. These departments must be better supported to facilitate dissemination of reliable, scientific information about climate change and its effects on health.