How an El Nino works

May 11, 2015

After one of the most dispiriting winters in memory, we could use a break from the weather. Alas, the winds may not be blowing in our direction.


As this Reuters graphic shows, El Ninos recur every three to eight years, and it has been five years since the last one.  The conditions for an El Nino, which is characterized by consecutive months of particularly warm Pacific Ocean temperatures, were met last June. Then in February, Pacific trade winds began to stagnate, allowing the warm waters and storm clouds to drift east toward the Americas.

Predictions from meteorologists in AustraliaJapan and the U.S. all recently increased their probability of an event this year, to as much as 70 percent. Aside from months of deluge in the U.S., the effects of an El Nino could include the warmest year on record, and then, if combined with further Arctic ice melt, a particularly cold winter in Europe.

When the strongest El Nino on record occurred in 1997-98, a 75-year-old Californian named Al Nino received angry phone calls demanding answers. If the rains come again this year, let’s hope people maintain better poise.

No comments so far

We welcome comments that advance the story through relevant opinion, anecdotes, links and data. If you see a comment that you believe is irrelevant or inappropriate, you can flag it to our editors by using the report abuse links. Views expressed in the comments do not represent those of Reuters. For more information on our comment policy, see