Federal forecasters now put the odds of an El Niño event developing by midsummer at 61%, a sharp upward shift that has farmers in the Great Plains, water managers across the drought-scarred West, and commodity traders around the world recalibrating their plans. The Climate Prediction Center issued the updated probability on April 9, 2026, in its latest ENSO Diagnostic Discussion, marking the agency’s clearest signal yet that the tropical Pacific is primed to flip from its recent La Niña phase into the warming pattern that has historically disrupted weather across continents.
Where the Pacific stands right now
As of early April 2026, the equatorial Pacific sits in ENSO-neutral territory. The weekly Niño-3.4 index, the benchmark measurement of sea surface temperatures in the central tropical Pacific, reads roughly negative 0.2 degrees Celsius, just a hair below the long-term average. That narrow gap is expected to close quickly. The CPC projects El Niño emerging during the May-through-July window and persisting through at least December 2026.
The agency’s companion ENSO strength probabilities table, also updated in April, breaks the forecast into intensity categories. It shows elevated chances for strong and very strong outcomes during the later overlapping seasons of 2026, with those probabilities climbing as the year progresses. Stronger events, defined by larger positive departures in the Niño-3.4 index, carry the power to reshape rainfall and temperature patterns from the American Southwest to the Indonesian archipelago. The table also preserves meaningful odds that the event stays weak or moderate, a reminder that the range of plausible outcomes remains wide. (The CPC has not published the specific percentage figures for each strength category in a format that allows precise citation here; readers should consult the table directly for the latest numbers.)
The CPC has formally moved its alert status to “Final La Niña Advisory / El Niño Watch.” Under the agency’s ENSO Alert System, that designation means observed trends and model guidance favor El Niño development within six months. It is not a guarantee but an operational trigger: the broader National Weather Service and partner agencies use it to begin adjusting seasonal outlooks, river forecasts, wildfire risk assessments, and drought monitoring.
Why the ocean backdrop matters
The El Niño signal is arriving against a backdrop of extraordinary ocean warmth. NOAA’s National Centers for Environmental Information reported that March 2025 ranked as the second-warmest March on record for global ocean surface temperatures. That benchmark is now a full year old and should be treated as background context rather than a direct reading of current conditions. No more recent NCEI global ocean temperature ranking is available in the public record cited here, so the precise state of ocean heat entering mid-2026 cannot be confirmed with the same specificity.
What can be said is that the long-term trajectory of ocean warming has been steeply upward, and nothing in the CPC’s April 2026 discussion suggests a reversal. El Niño adds its own pulse of heat to the tropical Pacific. When that pulse arrives on top of a baseline that has been running near record levels, even a moderate event can push global surface temperatures into territory with few precedents. The 2015-2016 super El Niño, which peaked with Niño-3.4 anomalies above 2.5 degrees Celsius, helped drive the hottest year in the modern record at the time.
What a 61% probability actually means
A 61% chance of El Niño by midsummer still leaves a 39% window in which the Pacific could stall in neutral territory or even cool again. The CPC builds its probabilities from an ensemble of dynamical and statistical models reviewed by multiple forecasters before release, making them the closest thing to a consensus scientific judgment on the state of the tropical Pacific. But they are probabilities, not certainties.
The intensity question adds another layer. The CPC strength table shows nonzero odds for strong and very strong outcomes, but the agency has not published detailed model diagnostics or individual forecaster commentary explaining how confident those upper-end estimates are. Historical analogs offer limited guidance because the background state of global ocean heat in 2026 is largely without precedent. No publicly available CPC modeling output specific to 2026 explains how record-warm baseline temperatures interact with the ENSO cycle to accelerate or dampen a developing event.
Regional impact projections are similarly preliminary. El Niño events typically bring wetter winters to the southern United States and drier conditions to parts of Southeast Asia and Australia, but the magnitude and geographic precision of those effects depend on the event’s peak strength and timing. The CPC has not yet issued seasonal precipitation or temperature outlooks that explicitly incorporate the April 2026 El Niño probabilities, so specific regional forecasts remain tentative.
The climate change question
Long-term ocean and atmospheric warming may be altering how ENSO behaves, from event frequency to the spatial pattern of warming across the Pacific. Some research suggests that very strong El Niño events could become more common in a warming climate, though the scientific literature is not settled on the question. The CPC products cited here are operational forecasting tools, not research papers; they do not attempt to separate how much of the projected 2026 El Niño signal comes from natural internal variability versus the influence of a warmer baseline climate.
That distinction matters for long-range planning. If the warming trend is making El Niño events more intense or more frequent, the playbook that water agencies and agricultural operations have relied on for decades may need updating. But without peer-reviewed studies focused specifically on ENSO behavior in the mid-2020s, quantifying that shift remains difficult.
What international forecasters and upcoming data will clarify
The CPC is not the only authority tracking the tropical Pacific. The World Meteorological Organization, Australia’s Bureau of Meteorology, and Columbia University’s International Research Institute for Climate and Society all issue independent ENSO outlooks. As of this writing, their most recent public updates have not been reviewed for this article, and incorporating their assessments would provide a fuller picture of global forecaster agreement or divergence on the likelihood and potential strength of a 2026 El Niño. Readers following the story should watch for those agencies’ next scheduled updates, which typically arrive on a monthly cycle.
For farmers, water districts, energy markets, and emergency managers, the El Niño Watch is a call to begin stress-testing operations against scenarios that include a moderate to strong event while keeping contingency plans ready in case the Pacific stays neutral. The CPC updates its ENSO outlook monthly, and each new release will narrow the forecast range. Key milestones to watch in May and June 2026 include updated Niño-3.4 readings, which will show whether the tropical Pacific is warming on schedule, and the next round of seasonal outlooks, which will begin translating El Niño probabilities into specific regional temperature and precipitation forecasts. Three categories of evidence would sharpen the picture considerably: post-April 2026 Niño-3.4 data confirming a warming trend, direct statements from named CPC forecasters about intensity risks, and corroborating assessments from the WMO, BOM, and IRI. Until those arrive, the 61% emergence probability and the elevated strength odds represent the best available estimate of where the tropical Pacific is headed.
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*This article was researched with the help of AI, with human editors creating the final content.
