If you’ve been following weather headlines lately, you may have done a double take. How can we have talk of a strong El Niño and La Niña at the same time? Isn’t that like saying it’s both day and night?
Well… yes and no.
Here is where some of the recent weather headlines have created more confusion than clarity. El Niño and La Niña are opposite phases of the same climate pattern in the tropical Pacific Ocean. El Niño occurs when waters in the central and eastern equatorial Pacific become warmer than normal, while La Niña occurs when those same waters become cooler than normal. Because they are opposite phases of the same Pacific pattern, we cannot have a traditional Pacific El Niño and Pacific La Niña occurring at the same time. That would be like trying to drive east and west on the same road at the same moment.
What we can have, however, is a strong Pacific El Niño developing while another cooler ocean pattern appears somewhere else. Some recent discussions have centered on the possibility of an Atlantic Niña, which is a separate pattern involving cooler-than-normal water near the equatorial Atlantic Ocean. It shares part of the La Niña name, but it is not the same phenomenon as the La Niña most people hear about in winter outlooks. One occurs in the Pacific, the other in the Atlantic, and each can affect the atmosphere differently.
The main climate story right now is the strengthening El Niño in the Pacific. NOAA reported on July 9 that El Niño was continuing to intensify, with a 97 percent chance that it would last through early spring 2027. NOAA also placed the probability of a very strong El Niño during the fall and early winter at 81 percent. That would place this event among the strongest observed since reliable records began in 1950.
Those are certainly attention-grabbing numbers, but they do not mean Missouri’s weather suddenly follows a predetermined script. El Niño is not a daily weather forecast, and it does not tell us whether it will rain in St. Louis next Tuesday or snow in Columbia on Christmas morning. It is better understood as a broad climate influence that changes the odds of certain weather patterns developing over several months.
During the summer, El Niño’s influence on Missouri is often less obvious than it becomes during the fall and winter. Our day-to-day weather is still controlled primarily by the location of the jet stream, large ridges of high pressure, approaching cold fronts, Gulf moisture, soil conditions and smaller disturbances moving through the atmosphere. A powerful ridge can still bring days of excessive heat. A stalled boundary can still produce repeated thunderstorms and flooding. El Niño may be working quietly in the background, but it does not control every cloud, storm or temperature change.
That is an important distinction because dramatic headlines sometimes make it sound as though El Niño arrives like a giant storm and begins producing immediate weather consequences. It does not. There is not El Niño cloud approaching Missouri and no specific day when we suddenly flip a switch into El Niño weather. Its effects develop gradually as the unusually warm Pacific Ocean changes tropical rainfall, atmospheric pressure and wind patterns. Those changes can eventually influence the position and strength of the jet stream across North America.
For Missouri, the greater interest comes as we move through fall and into winter. El Niño winters often feature a stronger and more active southern branch of the jet stream. That can bring more storm systems across the southern United States, while the northern tier of the country often experiences milder conditions. Missouri frequently sits somewhere between those primary zones, which makes our forecast much more complicated.
Depending on the exact storm track, Missouri could experience periods of rain, snow, ice or simply cold rain while areas only a few hundred miles away receive something completely different. That is nothing new for us. Missouri has always been in one of those frustrating battleground areas where warm Gulf air and cold Canadian air regularly collide. El Niño may influence where that battle line sets up, but it does not eliminate the uncertainty.
A strong El Niño can sometimes increase the number of storm systems passing near or south of Missouri, creating additional opportunities for winter precipitation. The key word is opportunities. More storms do not automatically mean more snow. If temperatures remain too warm, those systems may produce rain. If the cold air arrives at the right time, snow or freezing rain becomes more likely. The smallest shift in the storm track can make the difference between soaking rain, an ice storm, several inches of snow or nothing at all.
That is why I often say that El Niño loads the dice, but it does not decide how they land. A strong event can tilt the odds toward certain seasonal patterns, but individual storms, local temperatures and short-term atmospheric conditions still determine what happens in our neighborhood. NOAA also cautions that even the strongest El Niño events do not produce the typical impacts in every location.
There may also be implications for the Atlantic hurricane season. El Niño commonly increases upper-level winds over portions of the tropical Atlantic, producing wind shear that can disrupt developing tropical systems. NOAA’s 2026 Atlantic hurricane outlook favored a below-normal season, with El Niño listed as an important influence. That does not mean hurricanes cannot form or strike the United States. A quieter season can still produce one devastating storm, and history has taught us that the number of named storms is far less important than where those storms eventually travel.
An Atlantic Niña, should one develop, would add another piece to an already complicated atmospheric puzzle. Atlantic Niño and Niña events involve temperature changes in the equatorial Atlantic and may influence rainfall patterns and tropical development. Scientists continue studying how these Atlantic patterns interact with the Pacific, particularly when both oceans are experiencing unusual temperature changes.
For Missouri, however, we should resist the temptation to blame every hot day, thunderstorm or dry stretch on El Niño. Our summer weather remains heavily influenced by local and regional patterns. The recent heat and humidity are more directly connected to strong upper-level high pressure, abundant moisture and the position of frontal boundaries than to El Niño alone.
As summer gives way to fall, I will begin watching how El Niño influences the jet stream, drought conditions, Gulf moisture and the developing storm track. Those pieces will provide much more useful information about what Missouri may experience than the El Niño label by itself. We will also need to monitor Arctic air availability, snow cover across Canada, soil moisture and several other climate patterns that can either strengthen or weaken El Niño’s expected influence.
So, are El Niño and La Niña happening at the same time? Not in the same part of the Pacific Ocean. What we are really watching is a potentially historic Pacific El Niño alongside discussions about cooler conditions in parts of the Atlantic. They are separate ocean patterns with separate definitions, even though their similar names make the situation sound more contradictory than it truly is.
The bottom line is that Missouri could experience a more active and complicated weather pattern as we move toward winter, but no one can responsibly promise a snowy winter, a mild winter or a severe-weather outbreak based solely on El Niño. Weather does not work that neatly, especially in Missouri, where we can occasionally experience all four seasons before dinner.
For now, enjoy the summer, keep an eye on the daily forecast and remember that El Niño is a clue about where the atmosphere may be heading, not a guarantee of what will arrive at your front door.
I will keep watching it all from my window, because when the Pacific Ocean starts changing the atmosphere, Missouri usually finds a way to make the story interesting.
