(NEXSTAR) – You may have heard La Niña is over, and El Niño is getting ready to move in. It’s one thing to understand what that means for our weather, but what do the words “El Niño” and “La Niña” even mean?

Anyone who’s taken even a week of Spanish class knows the terms literally translate into “the boy” and “the girl.” But it’s not immediately obvious what that has to do with climate patterns.

The phenomenon’s original name, El Niño de Navidad, gives us a few more answers. It was coined by South American fisherman in the 1600s who noticed the unusually warm waters in the Pacific that define an El Niño season, the National Oceanic and Atmospheric Administration explains. They named the warm waters after Jesus, literally the “little boy of Christmas,” because El Niño typically peaks in December, around Christmastime.

That nickname stuck around for hundreds of years, but La Niña wasn’t really named until the 1980s, according to NOAA. That’s when scientists discovered the pattern of cooler-than-average ocean temperatures that come with La Niña.

La Niña essentially gets its name from being the opposite of El Niño. It has also been called “El Viejo, anti-El Niño, or simply a ‘cold event,'” NOAA says.

The occurrence of El Niño and La Niña are defined by water temperatures and winds in the Pacific, but they have an impact on the types of weather we see here on land.

As they reach their peak in winter, El Niño usually brings cold and wet conditions to California and the Southern U.S., and often leads to warm, dry winter in the Pacific Northwest and Midwest.

La Niña years, on the other hand, often correspond with busy and especially destructive hurricane seasons in the Atlantic. The La Niña climate pattern also usually splits the country in two, bringing a dry winter to the southern half and a wetter winter to the northern half.

Forecasters are expecting an El Niño pattern to reign this fall and winter.