This dataset contains water temperature data collected by boat tow on August 30, 2019 between approximately 8:00 AM and 12:15 PM Central Standard Time (CST) in the Milwaukee Estuary of Lake Michigan. The data includes measured water temperatures, depth of collection, water column depth, time of collection, and geospatial coordinates. The objective of this data collection was to produce longitudinal temperature profiles for analyses of water temperature fluctuation in the estuary in order to examine thermal interaction between the lake and river influences.