What's an El Niño?
El Niño is the warm phase of the ENSO cycle that rearranges Pacific temperatures and shifts weather patterns worldwide.
- El Niño warms the central and eastern tropical Pacific by weakening trade winds and suppressing upwelling.
- It creates a rainfall see-saw: wetter conditions in the southern U.S. and Peru, drier weather in Indonesia and Australia.
- A new event is forecast for 2026–27, likely bringing wetter winters to Georgia after limited summer relief.
- Impacts vary by event strength and are layered on top of human-driven climate change.
El Niño is one of Earth’s strongest natural climate drivers. It periodically warms large areas of the tropical Pacific Ocean, alters atmospheric circulation, and changes rainfall, temperature, and storm patterns across the globe.
What Is El Niño?
El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO). It features sea-surface temperatures at least 0.5 °C above average in the central and eastern equatorial Pacific for five consecutive months or longer. The name originated with 19th-century Peruvian fishermen who noticed unusually warm coastal waters near Christmas and called the phenomenon “the little boy” or “Christ child.”
How El Niño Forms
Under normal conditions, strong easterly trade winds push warm surface water westward toward Indonesia and Australia while cold water upwells along the South American coast. During El Niño the trade winds weaken or reverse, allowing warm water to shift eastward. This suppresses upwelling, raises eastern Pacific temperatures, and reverses the Walker Circulation through a process called Bjerknes feedback.
- Normal: Strong trades, warm water west, cold upwelling east
- El Niño: Weakened trades, warm water east, reduced upwelling
The Full ENSO Cycle
ENSO cycles through three phases every 2–7 years, each typically lasting 9–18 months: El Niño (warm), La Niña (cool, with stronger trades and cooler eastern waters), and neutral. Notable strong El Niño events occurred in 1997–98, 2015–16, and 2023–24.
Global Rainfall Impacts
El Niño shifts tropical rainfall eastward and alters the jet stream. Typical patterns include:
- Increased rain and flood risk: southern U.S., Gulf Coast, Peru, Ecuador
- Decreased rain and drought risk: Indonesia, Australia, Southeast Asia, northern U.S. and Canada
- Stronger events produce more reliable signals, especially in Northern Hemisphere winter
Outlook for Georgia in 2026
Georgia is currently in drought. NOAA’s Climate Prediction Center gives an 82 % chance of El Niño developing between May and July 2026 and a 96 % chance it persists through the 2026–27 winter. Summer rainfall influence is weak or even opposite, so drought may continue. The strongest effects arrive in fall and winter, when the Southeast typically sees above-average precipitation, more Gulf storms, and cooler periods that can ease drought conditions.
Sources
- NOAA Climate Prediction Center
- PMEL NOAA
