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

El Niño Watch

Climate conditions across the tropical Pacific were neutral when averaged over the month of September 2018, but trade wind anomalies and ocean warming in the eastern Pacific late in late September and early October were decidedly El Niño-like. There's a 70-75% chance of a weak El Niño during Northern Hemisphere winter 2018-19. 

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 September 2018. 

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

October 2018 ENSO update: Trick or treat!

October 11, 2018

On average, ENSO-neutral conditions still reigned across the tropical Pacific in September, but CPC blogger Emily Becker says October has brought some clearer signs of the development of El Niño.

Read more

Warm surface temperature anomalies appeared in the eastern tropical Pacific in late September and early October 2018.