Water temperature is an important factor controlling the biological activity and chemical reactions of a lake. Temperature also commonly controls lake water density and the potential for lake stratification or mixing. Relatively inexpensive equipment can be obtained and deployed to monitor lake temperatures on a continuous basis. King County has used relatively inexpensive continuous monitoring equipment to monitor the temperature of Lake Washington and Lake Union since 2005. This presentation will describe the history of King County’s continuous temperature data collection efforts and some of things we have learned over the years. Implications of some recent research on continuous temperature monitoring in small lakes will also be presented.