Significant obstacles to the production and management of hydropower in hilly basins are presented by climate change. This study looked at how the four hydroelectric projects in Nepal’s Dudhkoshi river basin might be affected by climate change and the hazards that come with it. For the common socioeconomic pathway 2-4.5, the output of one GCM, NESM3, was utilized to estimate temperature, precipitation, and consequently discharge in the near future (2031–2045 AD). It is possible to project 96 different scenarios that would represent all four projected climate change cases (warm-dry, warm-wet, cold-wet, and cold-dry), socioeconomic pathways (2-4.5 and 5-8.5), and different time frames (2031-2044 AD, 2061-2074 AD, and 2086-2099 AD) with additional research and fine-tuning of the hydrological model developed from HEC-HMS.