This Could Be the Strongest El Niño on Record

By Bob Henson, Yale Climate Connections – July 14, 2026
(Republished under a Creative Commons license. Jeff Masters and Irene Sans contributed.)

What’s Happening with Our Planet’s Temperature?

Imagine our Earth as a giant bathtub that’s been slowly heating up because of things people do, like burning coal and gas. That long-term heating is almost surely going to hit new record highs in 2027 — maybe even this year!

Why? Because a weather pattern called El Niño is forming. Think of El Niño as a giant release of heat from the ocean into the air. It’s like the ocean has been saving up warm water, and now it’s about to dump a lot of it out.

Important Point: New computer models from top climate scientists show this El Niño might be the strongest we’ve ever seen — by a “mind-blowing” amount.

Climate scientist Zeke Hausfather looked at 667 computer simulations from 14 different models. He says this El Niño is not only likely to be the strongest since we started keeping good records — it may beat the old record by a huge margin.

What Is El Niño (in Kid Terms)?

El Niño is when the water in the eastern part of the tropical Pacific Ocean gets warmer than usual. It’s like the ocean there turns up its heater for a few months to over a year.

• It’s the biggest single thing that changes global temperature and weather for months at a time.
• During its opposite, called La Niña (the ocean’s “cool mode”), heat gets stored in the ocean.
• When El Niño comes, that stored heat rises into the air and spikes global temperatures.

Usual side effects include:

• Drought in Indonesia, parts of South America, and Africa
• Wetter winters in the southern U.S.
• Fewer Atlantic hurricanes, more North Pacific hurricanes and typhoons

How Strong Could This El Niño Be?

Scientists have been expecting a 2026–27 El Niño for months. What’s shocking is that the models now agree more — and they all point to a record-breaker.

• Figure 1 (see original article) ranks every El Niño since 1877.
• The models together predict this one will peak about 3.6°C (6.5°F) warmer than average in the key ocean zone.
• That’s almost 1°C above the previous record in 149 years!

Hausfather puts it simply: “The models are forecasting something outside the envelope of anything we have ever observed.”

Important Point: The ocean itself is already in “uncharted waters” — not just the computer models.

A New Way to Measure: RONI vs. ONI

Because the whole planet’s oceans are warmer now, scientists made a new yardstick.

• ONI (Oceanic Niño Index): Old method measuring El Niño strength.
• RONI (Relative Oceanic Niño Index): New method that compares El Niño to the average temperature of all tropical oceans.

When using RONI:

• The old strongest event becomes 1982–83 (not 2015–16).
• The new event’s forecast is a bit less extreme but still has about 77% chance of being the strongest ever.

What Might Happen — and What Could Surprise Us?

Even a record El Niño doesn’t guarantee the usual weather impacts, but it raises the odds.

Most Likely Effects

• Southeast Asia: Less rain; Indonesia and Australia face fire risk.
• India: Weaker summer monsoon (already 20% below average in 2026).
• Atlantic storms: Slow start (only 1 weak storm by mid-July).
• Pacific storms: More activity (4 systems tracked in July).
• U.S. fall/winter: Wetter Sun Belt, drier Midwest/Pacific Northwest.
• Right now in U.S.: North is hot, South is cooler with flooding in Texas/Louisiana.

Important Point: Model agreement is reassuring, but it is not proof. The real ocean is already doing something we’ve never seen.

The Weird Cooling Mystery

Here’s a puzzle: while most oceans warm, the eastern tropical Pacific has cooled since the 1980s.

• The Pacific Decadal Oscillation (a long-term ocean pattern) has been negative every month since January 2020 — a 216-year record.
• La Niña has also been more common lately than El Niño.
• A 2025 study found this cooling can weaken El Niño’s usual global effects.

Scientists warn: “Historical precedent may no longer be a reliable guide” to El Niño impacts as human-caused warming grows.

Summary

Our planet’s human-caused heating, plus a rapidly forming El Niño, may produce the strongest El Niño in recorded history by the end of 2026 or in 2027. Top models give it a 77% chance of beating the record under the new RONI measure. This could bring droughts, fires, shifted rains, and unusual U.S. weather — but a mysterious Pacific cooling trend means old rules may not fully apply. The ocean is already in uncharted territory.

FAQ

1. What is El Niño in super simple terms?
It’s a period when the eastern tropical Pacific Ocean gets extra warm and pushes heat into the air, changing weather worldwide for months.

2. Why do scientists think this El Niño will be the strongest ever?
Hundreds of computer model runs from 14 models all point to a peak around 3.6°C above average — almost 1°C beyond any past event since 1877.

3. What is the difference between ONI and RONI?
ONI measures El Niño against its own historical ocean baseline. RONI adjusts for the fact that all tropical oceans are now warmer, giving a fairer modern comparison.

4. Will this definitely cause big weather disasters?
Not definitely. A record El Niño raises the odds of droughts, fires, and wet U.S. winters, but a strange Pacific cooling pattern may mute some effects.

5. Should we be worried?
The event is unusual and the oceans are in new territory. It’s a strong signal that climate change is making old weather patterns less predictable.