Amongst the Earth's most broad and influential natural climatic events are the El Nino and La Nina conditions in the Pacific. Everyone's heard of them, but we're not at all exactly sure what they are and how they affect the weather directly over our heads in Hawaii.

I poked around the web for educated details on these two phenomena, but found that a lot of the scientific jargon was way over my head and in some cases, contradictory. Here's how the National Oceanographic and Atmospheric Administration (NOAA) reckons them out; "El Niño and La Nina are phases of naturally occurring climate cycles over the Pacific Ocean and both are large-scale changes in sea-surface temperature across the eastern tropical Pacific. Usually, sea-surface readings off South America's west coast range from the 60s to 70s F, while they exceed 80 degrees F in the "warm pool" located in the central and western Pacific. This warm pool expands to cover the tropics during El Niño, but during La Niña, the easterly trade winds strengthen and cold upwelling along the equator and the West coast of South America intensifies. Sea-surface temperatures along the equator can fall as much as 7 degrees F below normal."

Um, yeah, OK ... I think I understand, but how do they affect the weather (and surf) in the islands? I didn't have complete faith in what I encountered online, so I went in search of a local expert who could provide an explanation in semi-lay terms and in context to Hawaii.


I was fortunate enough to find Roger Lukas, a Professor in the Department of Oceanography at the University of Hawaii. Lukas' faculty profile on the UH School of Ocean and Earth Science Technology (SOEST) site reads as follows; "teaches graduate courses at UH and conducts research in physical oceanography. His areas of research specialization are ocean-atmosphere interaction, seasonal-to-decadal climate variability, tropical ocean dynamics, and the distribution of oceanic water mass properties in the tropics and subtropics. He has been a Principal Investigator on more than 30 research grants by the National Science Foundation, NOAA, and the NASA. Lukas has been Chief Scientist of 14 oceanographic research cruises." Alrighty ... I think I found my man! Below, Roger answered my personal FAQ's about El Nino, La Nina, and Hawaii;

What initiates El Nino and La Nina and can they occur at the same time? El Nino and La Nina cannot occur at the same time; they are the opposite extremes of the El Nino/Southern Oscillation (ENSO) cycle. This cycle varies in its length from about 3-6 years. It is not clear whether it is self-sustaining, or whether it requires energy from some kind of triggering mechanism. Theories are clear about this distinction, but the observations are not.

Are they unique to the Pacific Ocean? Yes, El Nino/La Nina is a tropical Pacific Ocean phenomenon. However, their influence extends poleward from the tropics in both the ocean and atmosphere. The atmospheric response to El Nino in the Pacific does extend to the tropics of the Atlantic Ocean and the Indian Ocean. The Indian Ocean has a similar phenomenon known as the Indian Ocean Dipole, but it is less regular and shorter in duration. It interacts occasionally with the Pacific El Nino.

Is Hawaii currently under either condition now? If not, when was the last time, and when can expect it again? The tropical Pacific is experiencing weak La Nina conditions, which has been influencing the atmospheric circulation over Hawaii, especially this past winter. The next El Nino event has not started yet, and forecast models are mostly predicting "neutral" conditions for the next 6-9 months.

How do both affect hurricane production that puts Hawaii at risk? During El Nino events, there is a greater chance of Hawaii being affected by hurricanes, especially from storms that form near Hawaii. La Nina conditions are less favorable for hurricanes to form in the central Pacific, and cooler ocean temperatures between Hawaii and the eastern tropical Pacific tend to weaken storms that move towards Hawaii from the east.

How is either enhanced or reduced by global warming? This is an area of active research, and there are results supporting both possibilities. In general, the global climate models have somewhat low resolution to properly simulate the ENSO cycle. The models that do simulate ENSO are too computationally expensive to use for projecting climate changes. We need results on this question that are not so sensitive to the models that are used.

How does either affect Hawaii's climatic and surf conditions? Peak El Nino conditions occur during the winter months, and they tend to favor weaker winds and much less rainfall, (providing) great sunny weather for tourists. The storms near the Aleutian Islands are more intense than normal, and perhaps track closer to Hawaii (but without hitting the islands.) Thus, the surf on northern and western shores tends to be significantly larger than during La Nina years. La Nina winters tend to be wetter than average; at least more cloudy as we've seen this year.

Wow, this is really remarkable stuff. As one who's very interested in Earth sciences, the powerful mechanics of nature and the ocean never cease to amaze me. The hurricane information is especially gripping because the two most damaging hurricanes in Hawaii over the last three decades, Iwa (1982) and Iniki (1992), occurred during beefy El Nino conditions. Who knows how or if these storms were influenced by the presence of El Nino? It couldn't have helped the situation, that's for sure.


For some, this may just be another pile of useless information, but it definitely bears close monitoring because Hawaii's economy and quality of life has been and will be touched by the alternating presence of El Nino and La Nina periods. Awareness is always a handy thing for people that live in the middle of the big ol' Pacific. Hope this helped!

Thanks to Roger Lukas of the University of Hawaii for his time, expertise, and contribution to this article.