El Niño explained, but in pixel art

The 2026 El Niño, read straight from NOAA and NASA data through low-resolution maps and charts, one colored block at a time.

There is a strip of the Pacific Ocean, running along the equator, that is warmer than usual right now. Not by much, a little over one degree. That sounds small, but that extra degree tilts the odds toward a chain reaction that over the coming months can shift rainfall, harvests, fishing, and food prices across large parts of the planet. The phenomenon has a name you have probably heard before: El Niño.

In this post we try to explain it in plain terms, with a few maps made of characters (a kind of pixel art built from real NOAA and NASA data) and with numbers updated to 2026. The goal is that by the end you have a clear sense of what is happening, why it happens, and what to expect.

Let’s start with the facts: this year’s ocean

The most direct way to understand the state of the ocean is to look at how warm it is compared to its own average. This map shows the sea surface temperature anomaly for June 2026: how much warmer (toward red) or cooler (toward blue) each area is compared to the 1991–2020 average.

You can clearly see a warm tongue stretching across the Pacific along the equator, exactly the signature of El Niño. In the region that scientists call Niño 3.4 (a window of ocean in the central tropical Pacific, used as the official thermometer for the phenomenon) the single-month anomaly for June 2026 is about +1.5 degrees. The official index, which smooths over three months and uses its own reference period (more on that next), sits a touch lower at +1.4. Either way, that patch of ocean is more than a degree warmer than usual, and that is enough to nudge the atmosphere of the entire planet.

The index climate scientists watch

Rather than rely on a single map, scientists track one number, the ONI (Oceanic Niño Index). It is the Niño 3.4 anomaly averaged over three months at a time (a running mean), which smooths out the week-to-week noise and shows the underlying trend. When the ONI stays above +0.5 for several months in a row we call it El Niño. When it drops below -0.5 it is La Niña, its cold sibling.

In the chart each column is a period, red means warmer sea (El Niño) and blue means cooler sea (La Niña). A few tall red spikes jump out right away: 1982–83, 1997–98, 2015–16 and 2023–24, all of them among the strongest ever recorded, with 2015–16 the tallest of the group. On the far right sits 2026: after that 2023–24 event and a cooler phase in between, the index has climbed again quickly, going from negative values early in the year to +1.4 by June. Put simply, El Niño conditions are under way once more, and the ocean is still warming.

So what exactly is El Niño?

To understand it we need to go underwater for a moment. In normal conditions, steady winds blow along the equator from east to west, the trade winds. These winds push the warm surface water toward Asia and Australia, piling it up there in a kind of warm pool. On the opposite side, off the coast of South America, cold water rises from the deep to compensate. This process is called upwelling, and it brings nutrients to the surface: it is the reason the sea off Peru is one of the most fish-rich in the world.

During El Niño this engine stalls. The trade winds weaken, the warm water that was heaped up in the west slides back toward the east, and the cold upwelling shuts off. The result is that warm tongue you saw in the first map.

The catch (and the problem) is that the ocean and the atmosphere are linked. Where the sea warms, the air rises, clouds form and it rains. Where the sea cools, the air sinks and brings drought. By shifting the warm zone thousands of kilometers, El Niño shifts the rains too, and with them the harvests and the seasons of half the planet.

It is not the first time: 1997 vs 2010

To see how sharp the difference is, let’s compare two very different Decembers. December 1997 sat at the peak of one of the strongest El Niño events ever recorded, while December 2010 sat in the middle of a marked La Niña. Same maps, same color scale.

In the 1997 map the eastern Pacific (the South America side) is lit up in red: water far warmer than normal. In 2010 that same area is blue, meaning cooler than average. These are the two faces of the same oscillation, which in technical jargon is called ENSO (El Niño-Southern Oscillation). 2026 looks much more like the first case than the second.

One detail worth keeping in mind, because it matters for the next chart: these things move within a single year. 2010 actually opened with the tail of an El Niño, around +1.2 in February, then flipped hard the other way, down to -1.6 by November. So a calendar year does not get one clean label, which is why climate centers describe events by season rather than by year.

Why you should care: the heat records

Here is where it gets serious, and personal. El Niño does not stay locked in the Pacific: it releases heat from the ocean into the atmosphere, which is why El Niño years tend to be the warmest on record. This chart puts NASA’s global temperature record next to the state of the Pacific.

Each bar is a year, colored by its ENSO state: red for El Niño, blue for La Niña, gray for neutral. Two things stand out. First, the relentless climb: the planet keeps warming decade after decade. Second, the jumps to new records tend to land on El Niño years. Of the roughly twenty years that set a new record since 1950, more than half were El Niño years, well above the one-in-three you would expect by chance.

The effect is clearest if you look at the very strongest events: of the five biggest El Niño peaks since 1950, four were followed by a new record year. Those four are the stars in the chart, 1973, 1998, 2016 and 2024. The one that broke the pattern was 1982–83, a huge El Niño that did not produce a record year, and the likely reason sits outside the ocean entirely. The El Chichón volcano erupted in 1982, and the sulfate haze thrown up by big eruptions reflects sunlight and cools the surface for a year or two, which was roughly enough to cancel the El Niño bump.

2024 currently holds the record at +1.28 degrees above the 1951–1980 average. The link is not ironclad: 2023, for instance, set a record even though it began under La Niña, because the extra warming was already baked in. But the pattern is real. El Niño does not cause global warming, it stacks its extra heat on top of it, and that is often when the thermometers break.

What El Niño tends to do around the world

Beyond the global average, El Niño reorganizes regional climate, and the consequences fall on real people. Here is what tends to happen during an event like this one:

• Drought in Indonesia, Australia, parts of Southeast Asia and southern Africa, with a higher risk of wildfires and struggling harvests.
• Heavy rain and flooding along the coasts of Peru and Ecuador, in the southern United States, and in the Horn of Africa.
• Fisheries in trouble off South America: without the cold, nutrient-rich water, the anchovies disappear, and with them the livelihood of many coastal communities.
• Record global temperatures, as we just saw, because the ocean hands its stored heat to the atmosphere.
• Knock-on effects on food and health: weaker harvests can push up the price of rice, wheat and coffee, while shifting rainfall changes the spread of diseases like dengue and malaria.

Not all of these happen everywhere, or always with the same intensity: it depends on how strong the event turns out to be and how the local atmosphere responds. But this is the general picture, and it is why it pays to understand it ahead of time instead of learning about it from the news once the damage is done.

What to expect now

As of this writing, in September 2026, the ocean is saying clearly that El Niño is under way and consolidating. The next few months, the boreal autumn and winter, are usually when these events reach their peak. It is worth following the monthly updates from the climate centers (you will find them in the sources below), especially if you live or work in one of the more exposed areas, from agriculture to water management.

The good news is that El Niño, unlike many other phenomena, can be seen coming. We measure it, we track it, and we can prepare. Understanding what is happening in the ocean is the first step to not being caught off guard.

A note on the data and the visualizations

The maps in this article are built from real data, not artistic simulations. The June 2026 anomaly is computed as the difference between the observed temperature and the 1991–2020 average for the same month, from NOAA’s ERSSTv5 dataset. The 1997 and 2010 maps use the same dataset through NOAA CoastWatch, whose anomalies are measured against a 1971–2000 climatology rather than 1991–2020. Since the older baseline is cooler, those two maps read a few tenths of a degree warmer than they would on the 2026 map’s baseline, so do not compare the absolute numbers across maps. The patterns, and the 1997 against 2010 contrast, are unaffected. The ONI index comes from NOAA’s Climate Prediction Center. The global temperature series is NASA GISTEMP; each year is labeled El Niño, La Niña or neutral using the standard December-January-February ONI value. The visualizations are drawn character by character to give a grid-like, almost old-school pixel-map feel to the data.

Sources

• NOAA Climate Prediction Center, Oceanic Niño Index (ONI) and ENSO: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php
• NOAA Physical Sciences Laboratory, climate data and ONI: https://psl.noaa.gov/data/correlation/oni.data
• NOAA ERSSTv5 (Extended Reconstructed Sea Surface Temperature, version 5): https://www.ncei.noaa.gov/products/extended-reconstructed-sst
• NASA GISS Surface Temperature Analysis (GISTEMP v4): https://data.giss.nasa.gov/gistemp/
• NOAA Climate.gov, ENSO Blog (plain-language explainers and updates): https://www.climate.gov/news-features/blogs/enso
• World Meteorological Organization (WMO), El Niño/La Niña Update: https://wmo.int/topics/el-nino-la-nina
• International Research Institute for Climate and Society (IRI), Columbia University, ENSO forecasts: https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/
• USGS Volcano Hazards Program, on volcanic sulfate aerosols and their cooling effect on climate: https://www.usgs.gov/programs/VHP/volcanic-gases-can-be-harmful-health-vegetation-and-infrastructure

Data downloaded and last verified: September 2026.