Scientists have put Earth under a "El Niño watch" as they look for indications that a new climate pattern is emerging.
Its arrival may have a big effect on the whole planet, pushing global warming toward levels that climate experts have warned might be disastrous.
Rapid increases in average ocean temperatures since March have contributed to the growing conjecture that El Niño is about to arrive.
The pattern may indicate a brief break from an exceptionally long period of El Niño's opposite, La Niña, which scientists believe concluded in February.
Here's what you should know about it and what it may entail for the world and your town before it happens.
El Niño is linked to warmer-than-average seas around the equator in the Pacific Ocean, particularly in the eastern Pacific near South America.
Satellite data that enables scientists to detect water temperatures in the ocean's highest layers indicates the region has warmed dramatically in recent months.
In the absence of El Niño, warm surface waters are often pushed westward into Asia by Pacific trade winds. El Niño causes the winds to diminish.