There are several temperature gauges in or near Kerr and Gaston Lakes. The temperatures vary considerably from one gauge to another. In order to determine the temperatures we show in the column to the right, we use an algorithm of this and other readings along with air temperatures to project a range of temperatures that should cover the main lake, the coves and at several depths.
Here is a USGS gauge located in Buggs Island Lake (usually one of the coolest readings).