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

El Niño Watch

Temperature, winds, and cloudiness across the tropical Pacific were mostly neutral in August 2018, but they gave hints that support model forecasts of a transition to El Niño by later this fall (50-55% chance) or winter (65-70% chance). Below the ocean surface, a wave of warm water was spreading eastward, boosted by periods of weak trade winds.

More ENSO status information
Latest official ENSO update
Latest ENSO blog update

(image at left) Sea surface temperatures at the equator were warmer than average (orange, red) in much of the tropical Pacific in August 2018. A long-lasting warm spell in the central-eastern tropical Pacific is one of the criteria for El Niño.

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

El Niño is anchored in the tropical Pacific, but it affects seasonal climate "downstream" in the United States. This map shows some of the precipitation and temperature impacts we may experience if El Niño develops this winter as predicted, but not all impacts occur during every event, and their strength and exact location can vary. 

Typical U.S La Niña 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 impact on global climate during the Northern Hemisphere winter.  The map at left shows some of the precipitation and temperature patterns that might occur this coming winter if El Niño develops as predicted. However, not all impacts appear during every El Niño event.  

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

September 2018 ENSO Update: back to school

September 13, 2018

The last traces of La Niña disappeared across the tropical pacific in August, and the ocean and atmosphere began to drop hints of a developing El Niño. The Climate Prediction Center's Emily Becker explains what we're seeing.

Read more

(image at left) Splashes of pink across the bottom of the image reveal places where the easterly trade winds weakened in late August and early September 2018. Slack trade winds across the central and eastern tropical Pacific are one of the signs of El Niño.