Water temperature and the availability of cold-water refugia are important parameters during summer baseflows when stream water temperatures are at their maximum. The U.S. Geological Survey measured near-streambed and surface water temperatures along the lower Quinault River, on the Olympic Peninsula, Washington between August 9-12, 2016, during summer baseflow conditions. The survey occurred downstream from Lake Quinault from approximately River Kilometer (RK) 4 to approximately RK 49 (45 kilometers total). Near-streambed temperatures and water depths were measured at 1-second intervals, which occur on average at an approximately 1-meter water surface distance interval. Near-streambed temperature and depth were measured using an internally-logging sensor towed behind a raft traveling at ambient river velocity. Water surface temperatures measured by a second sensor towed behind the same watercraft and logging at 10-second intervals, were linearly interpolated to correspond to the 1-second interval. Data collected from August 9 through August 11 between RK 13 and RK 49 are referenced to a location that was concurrently measured with a Global Positioning System; data collected on August 12 from RK 4 to RK 13 do not include a reference location. Data are reported in a csv file consisting of date and time, depth, near-streambed temperature, water surface temperature, and spatial coordinates of latitude and longitude in North American Datum of 1983.In addition, ten cooler water features, in which water temperatures were 0.1 degree Celsius cooler than upstream or downstream locations, were identified from the longitudinal survey and field surveyed in August 2017. A temperature cross section was measured both upstream and downstream of the identified cooler water feature and one to five cross sections were measured along the length of each of the features. Cross sections included a depth to the riverbed and near-streambed temperature measurement at five, evenly spaced locations across the wetted width using an instant-read NIST-certified temperature sensor. All measurements at cross sections were point measurements taken during stable flow conditions between the approximate hours of 10:00 and 16:00 during the warming period of the diurnal cycle.