A total of 27 temperature sensors were deployed along the lower 90 miles of the Yakima River at 7 locations where cold water had been previously observed. These 7 cold-water areas had 3 to 6 temperature sensors installed to document the extent and duration of these cold-water areas and their impacts on mainstem temperatures of the Lower Yakima River. Cold-water areas included the mouths of tributaries, alongside channels, and within alcoves. Sensor deployments ranged from 1 to 2 years beginning in October 2018. All temperature data are included in the Yakima.temperatures.zip folder. Details of each monitoring location are provided in the site.locs.csv file. In addition to the raw data and site location information, an html file for each of the 7 cold water locations is provided so the user can visually explore the data. The 7 cold water areas included: Amon Creek at river mile (RM) 3.0, a side channel/tributary input located near I-182 at RM 4.7, a side channel at Fox Island near Van Giesen road at RM 8.5, A side channel in Benton CIty at RM 29, at Corral creek at RN 33.4, at Spring/Snipes creeks at RM 41.7, and in side channel and alvoce ares near Zillah, WA and RM 90.