The U.S. Geological Survey (USGS), in cooperation with the Houlton Band of Maliseet Indians (HBMI), has developed tools to assess the effects climate change on hydrology and water temperatures in the Meduxnekeag River Watershed in Maine. A USGS Scientific Investigations Report (SIR) report documents tools and datasets developed by the USGS to evaluate how climate change will affect the hydrology and water temperature in the watershed. Future hydrologic climate projections were developed based on changes to the precipitation and air-temperature input to the USGS Precipitation Runoff Modeling System (PRMS) (Markstrom and others, 2015) version 5.1.0. The baseline input data sets to the model were precipitation and air temperature data from 1980 to 2016. Future scenarios included increases in precipitation by 0-, 5- , 10, and 15-percent and increase in air temperature by 0, 3.6, 7.0, and 10.4 degrees Fahrenheit. The data include the input to and output from the PRMS developed to provide streamflow and water temperature simulations under selected changes in air temperature and precipitation. The data also includes shapefiles of the hydrologic response units and stream segments with identifiers matching those in the PRMS model. Markstrom, S.L., Regan, R.S., Hay, L.E., Viger, R.J., Webb, R.M.T., Payn, R.A., and LaFontaine, J.H., 2015, PRMS–IV, the precipitation-runoff modeling system, version 4: U.S. Geological Survey Techniques and Methods, book 6, chap. B7, 158 p., accessed October 1, 2018, at https://doi.org/10.3133/tm6B7.