It's not just El Niño: New climate phenomenon impacts Hawai'i rainfall

El Nino-Southern Oscillation (ENSO) is known to have a significant impact on climate across the Pacific, including Hawai'i, and adjacent continents. However, atmospheric scientists have now revealed that the Pacific Meridional Mode (PMM), another climate pattern that operates in the eastern Pacific Ocean, plays a major role in the variability of rainfall in Hawai'i.