Hydroclimate systems is an interdisciplinary research field focused on the complex interactions and feedback loops between the Earth's climate system and its hydrological cycle. It investigates the dynamics of water across atmospheric, terrestrial, and subsurface domains, including processes like precipitation, evaporation, transpiration, runoff, and storage, and how these are modulated by climate variability and change. This field examines these interactions across diverse spatial and temporal scales, seeking to understand past and present hydroclimatic conditions, project future changes, and assess their implications for water resources, ecosystems, and human societies.