A new study by researchers at the University of Hawai’i at Mānoa revealed that the Madden–Julian Oscillation (MJO), a large-scale tropical disturbance that travels eastward through the tropics every 30–60 days, significantly influences climate conditions in Hawai’i. Their research, published recently in the Journal of Hydrometeorology, showed that during active MJO phases, rainfall increases across the islands, especially on windward slopes. In contrast, suppressed MJO phases tend to produce drier conditions.