There are records of the El Niño weather phenomenon dating as far back as the 16th century when the Spanish came to Peru. For centuries, local fishermen noticed that in years where the temperature was warmer, they caught more fish.

It wasn't until the 1930s that climatologists determined the changing temperature of the Pacific Ocean off the western coast of South America — now called El Niño Southern Oscillation (ENSO) — impacts the weather on a global scale. Chances are your livelihood doesn't depend how many fish you catch. So aside from the decision to carry an umbrella or to take shelter in a storm, most of us don't give weather pattern changes a second thought.

However, El Niño and La Niña can adversely impact your business, your travel plans, your groceries and even your health.

You likely have some familiarity with El Niño since the "mother of all El Niños" was predicted this past fall. You couldn't turn on the television or hop online without seeing grim predictions and recollections of the disastrous floods, droughts and severe weather from the 1990s El Niño event.

Or maybe you're just familiar with the wrestler "El Niño" that Chris Farley portrayed on SNL.

But what exactly are El Niño and La Niña?

They are two sides of the same phenomena: El Niño Southern Oscillation. The El Niño weather pattern occurs when the Pacific Ocean of the western coast of South America along the equator is warmer than average. Since the ocean warms the atmosphere above it, this periodic warming has some big consequences.

According to the World Health Organization, 60 million people have been affected by this year's strong El Niño. When the effects of ENSO take hold, there are some overarching trends in seasonal weather across the globe and here in the United States.

El Niño

During El Niño periods, winters in the Southeastern regions of the U.S. tend to be wetter. This past winter, the South — particularly Louisiana — dealt with increased rainfall. This created a nightmare for home and business owners as they try to clean up the mess and rebuild, but these events also created a greater need for home improvement and landscaping.

Aside from direct injuries, flooding also causes health concerns like an increase in water- and vector-borne diseases and psychosocial effects. Dry El Niño winters in the forests of the Northwest make wildfires a greater threat as the spring and summer arrive, affecting timber industries and placing a greater strain on firefighters in the region. In the spring, the moisture shifts, bringing wetter conditions to the Southwest and drier than average in the Midwest.

This year's El Niño also caused the first drop in palm oil production in 20 years. Even if you haven't heard of palm oil, this dip will likely affect your wallet at the grocery store. Due to its low cholesterol content, palm oil is the most popular form of vegetable oil in the world. According to Bloomberg, "the tropical oil is used in everything from chocolate to soaps and biofuel."

The demand for this product may impact the prices you pay for everyday products such as margarine, breads, shampoos and detergents. This 2 percent drop will have lasting effects, even after this year's El Niño has faded.

La Niña

What about La Niña? El Niño's little sister doesn't get nearly as much attention, but she shouldn't be ignored. La Niña is just as capable as her brother to wreak meteorological havoc across the globe.

La Niña is the cooling phase of ENSO, where the temperatures in the equatorial Pacific are colder than average. It is one way the ocean balances out, generally after the warm phase of El Niño. Recent research has shown that the Pacific Ocean is going through a cooling trend, and we may be entering a La Niña phase before long.

Matthew Rosencrans, head of forecast operations for the National Weather Center's Climate Prediction Center told Farm Futures, "La Niña conditions are favored to develop during early fall, but it may be the second week of November when an actual La Niña is declared."

Currently, the Climate Prediction Center has a 75 percent chance for a La Niña starting this fall. Surfline states in an article that La Niña is not as pronounced in the U.S. during the summer months and that "impacts become more noticeable in the U.S. during the winter months."

In contrast to El Niño, La Niña produces hotter, drier conditions in the South and cold, wet weather in the Pacific Northwest. These conditions are not out of the ordinary for these regions, but the effects of ENSO could influence the moods and behaviors of residents.

Hot, dry conditions can lead to spikes in crime as residents grow more irritable. On the other hand, prolonged dreary weather in the Pacific Northwest can lead to increased instances of Seasonal Affective Disorder (SAD) or depression.

The rise of La Niña also brings concern to residents of Florida. As the News-Press reports in a story about the fading El Niño, "A La Niña trend could follow, some fear, and that may make the Atlantic Ocean and Gulf of Mexico more prone tropical storm and hurricane formation."

Tropical storms causes millions in damage, but in Florida the effects are all the more lasting. According to the Florida Department of Environmental Protection, "1 in 5 potential tourists would be less likely to come in the next 12 months because of storms." The economy is also affected significantly, as the department further explains that "80 percent of personal income received by state's residents comes from coastal areas."

Researchers have also discovered that La Niña periods bring greater risk of tornado outbreaks to Oklahoma, Texas, Louisiana, Arkansas and Missouri. Whether it is hurricanes or tornadoes, an increase in these life-changing storms is not a welcome thought.

Conclusion

Whether we realize it or not, ENSO has impacted our lives in our careers, produce, travel plans and even behaviors. It is more important to be aware of changes in your seasonal weather patterns than ever, as scientists are not sure how climate change may exacerbate the effects of ENSO.

Stronger El Niño and La Niña patterns will have the potential to bring more severe weather changes, making the impact to ourselves and our neighbors more prominent in all aspects of life.