Headwater stream temperatures measured within the Gribble Gap headwater catchment at 19 distinct locations. The dataset contains latitude and longitude values for each site, and stream temperatures at a 10 minute interval measured during spring (March 7, 2017 through April 4, 2017) and late summer (August 23, 2017 through September 19, 2017). Observations were collected by Dr. JP Gannon (Virginia Tech) and John Morgan (undergraduate student at Western Carolina University). All observations were made using Thermochron iButtons (Model DS1920L; resolution of 0.0625°C; manufacturer accuracy of +/- 0.5°C). Many sites were instrumented in duplicate, with duplicate sensors at a site indicated by 'A' or 'B' designations. Streamflow is reported at the Gribble Gap outlet in L/s, and all water temperature values are reported in °C. Sites extend from channel heads (W600, GC200, LS180) to the watershed outlet.