The data set includes temperature data from the base of the water column along the sediment interface of the East River near Crested Butte Colorado, USA, in support of ongoing study regarding groundwater/surface water exchange. The data were collected from 08/09/2016 to 08/31/2016 using a fiber-optic distributed temperature sensing system that has 1.01 m spatial resolution along the linear fiber-optic cable. During data analysis, the original 10 min measurments were averaged (arithmetic mean) for the entire period to potentially indicate colder groundwater inflows. Additionally, the standard devation for the entire measurement period for each distance along the cable was calculated to indicate buffered zones (reduced temperature standard deviation) that might result from upward water flow through the streambed.