The U.S. Geological Survey in cooperation with the Kentucky Geological Survey has been gathering temperature data on streams throughout Kentucky under a number of different programs for several decades. Periodic water temperature observations, which were made at a frequency of approximately once per month during the past 15 years, were analyzed with the aid of a computer program to describe the annual water temperature cycle at sites in the Commonwealth. Shown on a map of Kentucky, at each site of water-temperature collections, are maximum median monthly temperature, minimum median monthly temperature, and annual average temperature. Stream temperatures in Kentucky vary between 0 and 30 degrees Celsius (deg C) during the year. Maximum median monthly water temperatures occur in July and are typically between 23 and 27 deg C, whereas minimum median monthly water temperatures are recorded in January and are useually within the 2 to 6 deg C range. Annual average water temperatures are between 10 and 18 deg C. (Woodard-USGS)