El Niño & La Niña (El Niño-Southern Oscillation)

Spherical map of the tropical Pacific Ocean showing surface temperatures in April 2021 compared to average


La Niña—the cool phase of the El Niño-Southern Oscillation climate pattern—continued to weaken in April, and in early May, NOAA declared it officially over. Neutral conditions are likely to persist through summer.

Latest official ENSO update

Latest ENSO blog update

(image at left) Map of April 2021 sea surface temperatures compared to average showing the weak cool anomaly (departure from average) in the central-eastern tropical Pacific as La Niña faded over the month. NOAA Climate.gov image, based on NOAA EVL data.

El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific—the El Niño-Southern Oscillation, or “ENSO” for short.

The pattern can shift back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, precipitation, and winds.

These changes disrupt the large-scale air movements in the tropics, triggering a cascade of global side effects.

More about El Niño
What is El Niño in a nutshell?
Understanding El Niño (video)
ENSO alert system criteria
ENSO essentials
Educational Resources on ENSO

Globes showing typical climate impacts over the U.S. during El Niño and La Niñaca

El Niño is anchored in the tropical Pacific, but it affects climate "downstream" in the United States. In the summer, El Niño's primary influence on U.S. climate is on the hurricane season in both the eastern Pacific and the Atlantic. In winter, it influences the jet stream and the path of storms that move from the Pacific over the United States. 

Typical ENSO impacts
Winter temperature and precipitation
Hurricane season impacts
Current outlooks
6-10 day outlook
8-14 day outlook
1-month outlook
3-month outlook

El Niño and La Niña have their strongest influence on global climate during the Northern Hemisphere winter. During La Niña winters, the southern tier of the United States is often drier than normal. Northern Australia, Indonesia, and the Philippines are often wetter than normal. 

More information
ENSO's cascade of global impacts
The Walker Circulation
More maps of global impacts of La Niña and El Niño

ENSO model ensemble plume graph showing range of forecasts made for coming fall

May 2021 ENSO update: bye for now, La Niña!

May 13, 2021

Neutral conditions have returned to the tropical Pacific. Our blogger looks ahead to the rest of 2021.

Read more

(left) Climate model forecasts for the Niño3.4 Index. The average of all models (black line) favors La Niña re-emerging in the fall. NOAA Climate.gov image from University of Miami data.