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Written by Christopher W. Corwin, IAMElNino.com · Drafted with AI research assistance, fact-checked against NOAA CPC source data, and reviewed before publication.
El Niño conditions are now present, and the 2026 event is strengthening. NOAA CPC declared El Niño conditions on June 11, the IRI puts the probability at 100% through summer and autumn, and the weekly Niño 3.4 anomaly was sitting at +1.7°C as of June 17 — a strong weekly signal, though seasonal strength classification still depends on sustained values. What isn't settled yet is how strong this event gets, how fast it intensifies, and exactly what it delivers regionally when it peaks this winter.
Those questions get answered through data — specific numbers crossing specific thresholds, on specific dates. This post is a guide to all of it: the scheduled releases, the thresholds that matter, and the regional signals that will confirm or complicate the current forecast across the U.S., Australia, East Africa, and India.
Where Things Stand — June 25, 2026
Niño 3.4 weekly (IRI, June 17)+1.7°C
Niño 1+2 weekly+2.4°C
Relative Niño-3.4 / RONI outlookEl Niño — strengthening
IRI El Niño probability (JJA–DJF)100% JJA–SON · 99% OND–DJF
Indian Ocean Dipole (BoM DMI, June 14)−0.13°C — neutral, positive phase forecast
CPC advisory statusEl Niño Advisory — strengthen into winter
The Threshold Table
Before the calendar, the benchmarks. These are the specific numbers that trigger classification upgrades, post-worthy news pegs, and meaningful shifts in the regional forecast. Not all of them will be crossed — but each one that is represents a step-change in what this event means on the ground.
| Metric |
Threshold |
What It Means |
| Niño 3.4 weekly |
+2.0°C |
Weekly Niño 3.4 above +2.0°C would be an early warning that seasonal values may be tracking toward very strong territory. Peak 1997-98 was ~+2.3°C; 2015-16 was ~+2.6°C seasonally. |
| Niño 1+2 weekly |
+3.0°C |
Extreme eastern Pacific signal. Already at +2.4°C. A crossing here confirms a canonical east-based event, not a central Pacific Modoki. |
| RONI seasonal |
+1.0°C |
NOAA's "strong" El Niño classification threshold. The event is in El Niño territory; this confirms strong. Watch the JJA seasonal value. |
| RONI seasonal |
+1.5°C |
Very strong classification. At this level, regional teleconnections — particularly for the U.S. southern tier, Australia, and East Africa — become much more reliable. |
| BoM Dipole Mode Index |
+0.4°C |
Bureau of Meteorology's positive IOD watch threshold. Currently at −0.13°C; sustained values above +0.4°C would support a positive IOD classification. Declaration in July or August would be notably early. |
| BoM Dipole Mode Index |
+1.0°C |
Strong positive IOD. At this level the Australia drought signal and East Africa flood risk both amplify significantly. |
| CPC Discussion language |
"Westerly wind anomalies" |
When CPC explicitly describes sustained westerly wind anomalies across the central Pacific, the Walker Circulation breakdown is underway — the atmospheric half of El Niño has fully coupled. |
The Data Calendar
ENSO science advances on a schedule. Here are the releases that matter most between now and the event's expected peak in November–January.
July 9, 2026
NOAA CPC ENSO Diagnostic Discussion
The next scheduled official advisory. This is the primary monthly update on RONI classification, atmospheric coupling status, and the seasonal outlook. Watch for any upgrade in language from "strengthening" to "strong" and for the first official reference to winter peak timing. This is the anchor content event for July.
July — Weekly
IRI Niño 3.4 Weekly Readings
At +1.7°C and climbing, a crossing above +2.0°C sustained over multiple weeks would be the first confirmation that this event is tracking into very strong territory. The IRI updates weekly SST values on Tuesdays. Watch the trend, not just any single week's reading.
July — Monthly
Bureau of Meteorology IOD Update
BoM publishes the Dipole Mode Index monthly. The first reading above +0.4°C triggers a formal positive IOD declaration — confirming the two-ocean pattern flagged by the WMO in June. The development window is July through October; a declaration in July or August would be notably early.
Early August
IRI/CPC Model Plume Update
The IRI publishes updated multi-model ensemble plumes in the first week of August. This is the best look at model consensus for the NDJ peak. If the ensemble median pushes above +2.0°C for the peak season, very strong classification becomes the central scenario, not just a tail risk.
August 13, 2026
NOAA CPC ENSO Diagnostic Discussion
The August advisory is critical because it's the first one likely to include explicit winter peak language. Watch for the seasonal SST consolidation peak estimate — in June the CPC median was sitting around +1.9°C for NDJ. Any upward revision here matters for the regional outlooks.
September — Weekly
Niño 1+2 Watch: +3.0°C
The Niño 1+2 region is already at +2.4°C and has been running significantly warmer than Niño 3.4 — the hallmark of the east-based event first covered here in June. A crossing above +3.0°C in this region through September-October would put the eastern Pacific signal in extreme territory and sharpen the Peru and Ecuador impact forecasts considerably.
October 2026
NOAA Official U.S. Winter Outlook
NOAA CPC releases official temperature and precipitation probability maps for December-February, explicitly citing El Niño as the primary driver. This triggers the full set of regional post updates — California, Texas, Midwest, and Pacific Northwest — with the official numbers. Pre-draft the regional posts in September; fill in the official probabilities the day the outlook drops.
Global Signals: What to Watch by Region
El Niño's fingerprints show up differently depending on where you're looking. These are the regional signals worth tracking from now through the event's peak.
Australia
Signal: Drier · Confidence: High
El Niño alone points drier across eastern and northwestern Australia. A co-developing positive IOD reinforces that signal significantly. Watch BoM's ENSO Outlook for any shift to "El Niño" language (currently on watch), and the Australian Bureau's rainfall outlooks for Queensland and New South Wales, which should begin trending below normal by August-September. BoM drought declarations would be a clear follow-up post trigger.
East Africa
Signal: Wetter (OND) · Confidence: High
The October-December short rains in equatorial and southern East Africa — Kenya, Uganda, Tanzania, Rwanda, Somalia — are expected significantly above normal. ICPAC has already flagged elevated flood, flash flood, and landslide risk for this window. The northern Greater Horn faces the opposite signal: drier-than-normal through July-September before the wet pattern takes hold. Watch ICPAC's monthly outlooks for any upgrades in the flood risk language.
India
Signal: Below Normal · Confidence: Moderate
IMD's April forecast put the 2026 southwest monsoon at 92% of the long-period average, later revised to 90% in late May — both classified as below normal. The complicating factor: a developing positive IOD tends to support India's monsoon, partially offsetting El Niño's suppression. The net signal is below normal nationally but with genuine regional uncertainty. Watch IMD's monthly monsoon updates through September for actual performance versus forecast, and whether the IOD development shifts the balance.
U.S. Southern Tier
Signal: Wetter (OND–MAM) · Confidence: High
The southward-shifted subtropical jet stream is the most reliable U.S. El Niño signal. California, the Southwest, Texas, and the Gulf Coast all sit in the favored-above-normal precipitation corridor for a strong-to-very-strong event. The NOAA Winter Outlook in October will put official probability numbers on this. Before that, watch for the first atmospheric river events attributed to the developing El Niño pattern in October-November as the jet stream begins shifting.
U.S. Pacific Northwest
Signal: Warmer/Drier · Confidence: Moderate-High
The same jet stream shift that wets the southern tier tends to dry out the Pacific Northwest. Above-normal temperatures and below-normal precipitation are the favored signals for Washington, Oregon, and northern Idaho during strong El Niño winters. Ski season outlooks and snowpack forecasts for the Cascades will start drawing El Niño comparisons by October.
Indonesia / Maritime Continent
Signal: Drier · Confidence: High
One of El Niño's most consistent signals globally. Cool SST anomalies near Indonesia suppress convection and rainfall during a positive IOD event, compounding El Niño's already-drying effect on the Maritime Continent. Fire weather risk increases markedly. BMKG (Indonesia's meteorological agency) publishes drought and fire risk outlooks monthly — worth checking through the August-November dry-season peak.
The Peak Scenario
The current central forecast — drawn from the CPC's June consolidation and the IRI model plume — points toward a peak Niño 3.4 anomaly somewhere around +1.9°C to +2.3°C during November–January, which would place this event firmly in the "strong" category and potentially at the lower end of "very strong." That range would rank among the more significant El Niño events in the post-1950 record.
Whether it pushes higher — toward the +2.6°C that defined 2015-16 or the territory occupied by 1997-98 — depends on how the next three months of Kelvin wave activity, MJO forcing, and atmospheric coupling unfold. The subsurface reservoir is well-loaded. The eastern Pacific Niño 1+2 region, already at +2.4°C, suggests that when the peak does arrive, it will have a strong eastern Pacific character. That's important for regional impacts: east-based events tend to produce more reliable and more intense teleconnections for the U.S. southern tier than central Pacific events do.
Bottom Line
The 2026 El Niño is confirmed, strengthening, and tracking toward a strong-to-very-strong peak this winter. The numbers that matter most between now and October: Niño 3.4 crossing +2.0°C, RONI reaching +1.5°C for the seasonal classification, the BoM DMI crossing +0.4°C for a positive IOD declaration, and the NOAA Winter Outlook in October putting official probability numbers on the U.S. regional picture. Every one of those is a threshold worth watching — and this site will cover each one as it happens.
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Data sources: NOAA CPC ENSO Diagnostic Discussion (June 11, 2026); IRI ENSO Quick Look and weekly Niño 3.4 (June 17, 2026); Bureau of Meteorology IOD and ENSO Outlook (June 14, 2026); WMO Global Seasonal Climate Update (June 2026); IMD Southwest Monsoon Forecast (April 2026); ICPAC Greater Horn of Africa Outlook (June 2026); Climate Impact Company IOD Outlook (March 2026).
Editorial note: This post was researched and written by Christopher W. Corwin with AI writing assistance. All data points were verified against cited primary sources prior to publication. IAMElNino.com is an independent monitoring site and is not affiliated with NOAA, WMO, or any government agency.