<p>The global community is growing increasingly concerned about the impact of climate change, particularly the expected increase in droughts and associated depletion of water resources in the coming years. However, specific future projections using high-resolution climate simulations focusing on the frequency and intensity of hydrological droughts in Japan are currently lacking. In this study, we examined the effects of climate change on hydrological droughts in central Japan through hydrological model simulations utilizing climate projections from a high-resolution ensemble dataset downscaled to a 5-km scale. The results indicated a decrease in streamflow during summer as climate change progressed, corresponding to increased drought events. In addition, there was a considerable increase in the number of consecutive hydrological drought days, reaching an unprecedented level. Moreover, the application of self-organizing maps (SOMs) to atmospheric data allowed for the examination of the relationships between summer river discharge and climate/weather patterns under future and present climate simulations. The SOM analysis indicated that the impact of climate change on river discharge varies by climate/weather patterns. Hydrological drought events tend to be stronger in certain future patterns. In particular, future projections indicate an increase in monthly-scale hydrological droughts in climatic backgrounds characterized by southerly and easterly airflows as precipitation decreases and evapotranspiration increases. The results of this study provide valuable insights for considering adaptation strategies concerning dry-season water use in future climate scenarios.</p>