By Laura Anderson, Welp Magazine. Published and last updated October 9, 2026.
El Nino heat waves are the reason 2026 feels so hot, and the worst may still be ahead. A very strong El Nino is building in the Pacific, and forecasters say it could rival the strongest on record. Here is the science of how it works, what the latest numbers say, and why the heat is expected to peak in 2027.
Quick Facts: El Nino Heat Waves 2026
- What it is: El Nino is a warming of the central and eastern tropical Pacific that reshapes weather worldwide.
- Status: NOAA’s October 8, 2026 update says El Nino is strengthening and likely to be strong to very strong.
- Odds: NOAA puts the chance of a historically strong event at 83% for October to December.
- Why El Nino heat waves happen: The Pacific releases stored heat into the air and shifts the jet stream and monsoons.
- Next risk year for El Nino heat waves: Analysts say 2027 is more likely than 2026 to set a new global temperature record.
What Is El Nino and Why Is 2026 Different?
El Nino is a natural warming of the central and eastern tropical Pacific Ocean that changes weather patterns around the world. The World Meteorological Organization declared the 2026 event began on June 2. NOAA’s October 8 update says it is strengthening and likely to become strong to very strong, with an 83% chance of historic strength for October to December. The next update is due November 12.
Some outlets call it a super El Nino. That label is informal, and sources disagree on whether it is already the strongest on record, so we use NOAA’s official wording.
Why Do El Nino Heat Waves Happen?
El Nino heat waves happen because the ocean moves stored heat into the air and rearranges the weather systems that carry it. It is a chain reaction in four steps.
| Step | What happens | Heat effect |
|---|---|---|
| 1. Trade winds weaken | Warm water spreads east across the Pacific | Ocean surface warms |
| 2. Ocean releases heat | Stored heat rises into the atmosphere | Global air temperature climbs |
| 3. Jet stream shifts | Storm tracks and high pressure move | Heat domes form in new places |
| 4. Monsoons falter | Rains arrive late or weak | Longer, deadlier heat on land |
Step 1 and 2: The Ocean Lets Go of Its Heat
Normally trade winds push warm water west toward Asia and Australia. In El Nino those winds weaken, and warm water spreads east. The ocean then releases a huge store of heat to the atmosphere, which is why El Nino years often rank among the hottest ever recorded. NASA and Scripps both describe this as one of the planet’s biggest natural heat release valves.
Step 3 and 4: Jet Streams and Monsoons Shift
The warm Pacific also moves the jet stream, which steers storms and high pressure. Heat domes can settle over regions that usually stay cooler, which is how El Nino heat waves can strike far from the Pacific. In South Asia, a late or weak monsoon means less cooling rain and longer stretches of dangerous heat.
How Hot Could El Nino Heat Waves Get?
A typical El Nino adds roughly 0.2 C to global average temperature, according to the UK House of Commons Library. This one sits on top of long term warming, so its effect is expected to be larger. Carbon Brief says 2026 is on track to be the second warmest year, with a 19% chance of beating 2024. It adds that a strong El Nino makes 2027 the more likely year to set a record.
Science News reported that daily sea surface temperature in the key Pacific region hit 3.08 C above the 1991 to 2020 average on September 21, higher than any earlier event. Global average sea surface temperature also set an all time high of 21.1 C in June.
The Human Cost of El Nino Heat Waves
A Climate Impact Lab estimate reported by CNN projects about 451,000 heat related deaths linked to the event between June 2026 and February 2027, on top of normal heat deaths. This is a model estimate, and researchers expect it could rise. The UN’s World Food Programme warns that nearly 50 million more people in vulnerable communities could be pushed into acute hunger.
Is Climate Change Making El Nino Worse?
NASA says climate change does not cause El Nino, but a warmer baseline makes its effects stronger. One study found El Nino linked sea surface temperature extremes have grown about 10% more intense than before 1960. In plain terms: El Nino lights the match, and global warming has already soaked the room in fuel.
Looking ahead, El Nino heat waves are likely to be most intense between December and February, and the lag in the atmosphere means El Nino heat waves may keep global temperatures high well into 2027.
What Is Still Uncertain?
- Whether the event will be officially declared the strongest on record. NOAA has not done so yet.
- How high it will peak. The Washington Post’s tracking projects a December peak far above past events, but forecasts can shift.
- Exact death tolls. Current figures are model based.
Where Are El Nino Heat Waves Hitting Asia?
Asia is at the center of the risk. The World Meteorological Organization confirmed on September 3 that the event is firmly established and will intensify into a very strong one, raising the odds of floods, drought and extreme heat well into 2027. Red Cross and Red Crescent planning for the region lists heat waves and floods in Nepal, floods in Bangladesh and Pakistan, cyclones in the Philippines, and heightened heat wave, typhoon and flood risk in Japan, South Korea and China.
The Climate Impact Lab projection behind the 451,000 figure estimates about 6,500 extra heat deaths in the Philippines and nearly 20,000 across Southeast Asia. Indonesia has already declared drought emergency status in several districts. One caution: the Philippines may see extra rain if a positive Indian Ocean Dipole offsets the usual drying, so not every El Nino heat wave in Asia looks the same.
What Happened in Nepal, and Is El Nino to Blame?
On August 26, 2026, a huge piece of ice and rock broke loose high in the Himalaya and sent a flash flood and debris flow down the Bhote Koshi and Trishuli rivers. Wikipedia’s running tally lists at least 1,454 dead and 5,285 missing as of October 4, while Britannica cites more than 1,300 dead and about 5,500 missing. Nepal has reportedly ended its search, and officials estimate losses of $4 billion to $7 billion.
We found no source that blames El Nino directly. Scientists describe an enormous landslide and glacier collapse. Heat can destabilize mountain ice, but a firm link to this event is not established, and the death counts are still changing. Our El Nino impact guide covers Nepal in more detail.
Europe: Weaker and More Uncertain Effects
The UK Met Office says El Nino effects in Europe are typically indirect. It can raise the odds of a milder, wetter and windier autumn and early winter, and it can bring colder, calmer spells in late winter. The EU’s Joint Research Centre sees a different possibility: a strong event could flip the usual pattern and leave Europe warmer than normal, with that warmth building toward spring 2027. Euronews reports it is unlikely to affect Europe’s 2026 summer.
Which Countries Are Safest From El Nino Heat Waves?
No country is fully safe, because El Nino moves food prices, shipping and energy markets worldwide. But exposure is uneven. One ranking site says effects are strongest in the tropics and weakest in Europe and northern Asia. Southern Brazil and Argentina often get helpful rain, and one tracker rates the net effect for the United States as mildly favorable. Countries with strong irrigation, food reserves and early warning systems usually cope best.
References and Further Reading
- NOAA Climate Prediction Center: ENSO Diagnostic Discussion
- UK Met Office: El Nino declared for 2026
- UNDP: A very strong El Nino is building in Asia and the Pacific
- Britannica: Nepal floods of 2026
What Happens Next? Read the Rest of This Series
This guide is the first of three. Next, see El Nino Impact 2026 for the regional breakdown across India, Australia and the Americas. Then read how climate technology startups are responding to hotter grids and heat. For more explainers, browse our Environment coverage.
How Do Scientists Measure the Pacific Warming?
Forecasters track the tropical Pacific with ocean buoys, satellites and computer models. The headline number is the Nino 3.4 index, which compares sea surface temperature in a box of ocean near the equator with its long term average. When that anomaly stays above +0.5 C for several months, the climate pattern is classed as a warm phase. Readings above +1.5 C are usually called strong, and NOAA reported about +2.1 C last month.
Different agencies use different baselines, so their numbers are not directly interchangeable. NOAA’s relative index adjusts for background ocean warming, while the WMO uses an older reference period and reports a higher figure. That is one reason headlines about a record can disagree, even when everyone is looking at the same ocean.
How Long Does a Warm Phase Last?
Warm phases usually last nine to twelve months, then fade as trade winds recover. Many peak in late autumn or winter in the Northern Hemisphere, which is why forecasters expect the strongest effects between December and February. Heat in the atmosphere lags the ocean by a few months, so the global temperature spike often arrives after the ocean peak. That lag is the main reason analysts point to 2027 for a possible new annual record.
The opposite phase, La Nina, cools the same region and tends to lower global temperatures. A swing from one to the other can change harvests, rainfall and wildfire seasons within a single year.
How We Reported This
This article is based on NOAA’s Climate Prediction Center, NASA, Carbon Brief, Science News, CNN, the UN and the Union of Concerned Scientists, as of October 9, 2026. Where sources disagree, we say so. We update this page when NOAA releases new data. Further reading: NASA on El Nino and CNN on heat deaths.
Frequently Asked Questions
Why do El Nino heat waves happen?
El Nino heat waves are not created directly. The event moves enormous amounts of stored Pacific Ocean heat into the atmosphere and shifts the jet stream and monsoons, which lets heat build in many regions at once.
How strong is the 2026 El Nino?
NOAA’s October 8, 2026 update says it is strengthening and likely to be strong to very strong. The Nino 3.4 index reached about +2.1 C last month, and NOAA gives an 83% chance of historic strength for October to December.
Is 2026 the hottest year on record?
Not yet. Carbon Brief says 2026 is on track to be the second warmest year, with a 19% chance of beating 2024. A strong El Nino makes 2027 the more likely record year.
Is climate change making El Nino worse?
NASA says climate change does not cause El Nino, but warming makes its effects stronger. One study found El Nino related sea surface temperature extremes are about 10% more intense than before 1960.
How many people could die from El Nino heat?
A Climate Impact Lab estimate reported by CNN projects about 451,000 heat deaths linked to the event between June 2026 and February 2027. It is a model estimate, not a count.
Which countries are most affected by El Nino heat waves?
The tropics and subtropics are hit hardest, including India, Indonesia, the Philippines, Australia, Peru and Central America. Agencies expect the worst heat between December 2026 and February 2027.
Which countries are safe from El Nino?
No country is completely safe, since El Nino affects global food and energy prices. Exposure is weakest in Europe and northern Asia, while southern Brazil, Argentina and parts of the United States can see benefits such as extra rain.
What happened in Nepal in 2026?
A glacier and rock ice collapse on August 26 triggered a deadly flash flood along the Bhote Koshi and Trishuli rivers. Counts differ by source, but more than 1,300 people were reported dead and thousands missing. No source has directly blamed El Nino.
How does El Nino affect Europe?
Effects are indirect and uncertain. The Met Office says it can bring a milder, wetter, windier autumn and early winter, and sometimes a colder late winter.
