Hydrological extremes including extreme precipitation events and dry spells play a key role in modulating regional water and energy cycle in addition to their significant socioeconomic impacts. This talk discusses the seasonality, interannual variability, long-term trends, large-scale organization, and global model representation of hydrological extremes occurring in the contiguous United States. Specifically, we show that one of the major modes of interannual variability in the western US dryness in boreal summer is closely tied to the non-modal growth of a subseasonal-scale atmospheric disturbance over the North Pacific and is “seeded” by precipitation anomalies in East Asia. Also discussed are the implications of this discovery for the predictability of US precipitation in boreal summer.