Forecast Watch: El Niño Likely This Summer, With Global Heat and Regional Weather Shifts Expected

A summer shift in the Pacific could shape the rest of the year

A potentially strong El Niño weather pattern is likely to emerge this summer and persist through the rest of the year, according to the latest official forecast from the National Oceanic and Atmospheric Administration. Forecasters estimate there is a 62% chance that El Niño develops between June and August, a window that places the possible onset squarely in the heart of the Northern Hemisphere summer.

El Niño is a naturally occurring climate pattern tied to changes in the tropical Pacific Ocean and the atmosphere above it. Even though it is cyclical, its arrival is closely watched because it can alter weather patterns around the world and influence global temperature averages. Scientists also emphasize that El Niño unfolds against the backdrop of ongoing human-caused global warming, which is driven primarily by the burning of fossil fuels.

What El Niño is and why trade winds matter

El Niño occurs when trade winds weaken, allowing vast volumes of warm ocean water to move from the Eastern Pacific toward the Americas. That shift in winds and ocean temperatures can change where heat is concentrated in the Pacific and how that heat interacts with the atmosphere.

In practical terms, El Niño is often discussed as a “pattern,” but it is better understood as a coupled ocean-atmosphere fluctuation. When the Eastern Pacific is hotter than usual, the ocean can transfer more heat and moisture into the air, influencing storm tracks, rainfall patterns, and temperature extremes far beyond the tropics.

Daniel Swain, a climate scientist with the University of California Agriculture and Natural Resources, said that while evidence is still early, the event could be significant in 2026 and linger into 2027. The timing matters because El Niño’s influence on global temperatures can extend beyond its initial development, with impacts often peaking after the pattern is established.

Why El Niño is linked to record global heat

A strong El Niño tends to drive up average global temperatures. Historically, the hottest years on record generally occur in years when El Niño is active. One reason is that El Niño is associated with warmer-than-usual conditions in the Eastern Pacific, which can raise the global average when combined with warmth elsewhere.

Swain described El Niño’s role in the broader climate system as a process that helps release heat from deeper ocean layers that had been temporarily stored. In his explanation, El Niño allows that “subducted” heat to be unearthed, which can add to the warmth felt at the surface and in the atmosphere.

This dynamic was evident in 2023 and 2024, when a long, strong El Niño helped shatter global temperature records. In that period, 2023 set a new record for the hottest year ever recorded on Earth, only to be surpassed by temperatures in 2024.

Zeke Hausfather, a research scientist at Berkeley Earth and climate research lead at technology company Stripe, said that if a strong El Niño develops, it could boost temperatures in 2026 somewhat, but may have a particularly large effect on temperatures in 2027. In his assessment, that could put 2027 on track to be the warmest year on record after 2024.

El Niño is not the main cause of warming, but it can amplify it

Scientists stress that El Niño is only one driver of record-breaking heat. The main reason the planet is warming is human-caused global warming associated with burning fossil fuels. That distinction is important for understanding why recent years have been exceptionally warm even beyond the influence of natural cycles.

Even without El Niño, the planet has been running hot: last year was in the top three hottest years on record. El Niño can add to that baseline warmth, but it does not replace the underlying trend. Instead, it can temporarily push global temperatures higher than they would otherwise be, and it can alter where and how extreme weather shows up.

Regional weather: where the impacts can be most consequential

While global temperature averages often dominate headlines, El Niño’s most meaningful effects for many people are regional. It can shift rainfall patterns, influence drought severity, and change the background conditions that affect storms and wildfires.

Swain noted that El Niño’s regional patterns can be among its most dangerous effects. In his view, it can mean more heat waves and tangibly warmer temperatures, but the broader concern is what it implies for other hazards: more energy for storms, heavier downpours, more intensive droughts, and more extreme wildfires.

Southern United States: wetter and cooler tendencies, with limits

In the United States, El Niño is often associated with more rain and cooler temperatures across the Southern states. Those conditions can help control droughts and tamp down wildfire activity, at least in some areas and for some period of time.

However, the benefits are not guaranteed and may not be sufficient to reverse long-term deficits. The Southwest, for example, is in the grip of such a severe drought that one year of wetter weather would not be enough to fully replenish reservoirs, according to a new analysis by the National Integrated Drought Information System.

This is a crucial nuance for water planning and public expectations. A single season of increased precipitation can improve short-term conditions, but it may not undo the impacts of prolonged dryness, especially where reservoirs and groundwater have been stressed over multiple years.

Drought risk elsewhere: extra heat can worsen dryness

El Niño’s influence is not uniform, and the same pattern that brings rain to one region can contribute to dryness in another. The added global heat associated with El Niño can also drive more severe droughts in parts of the world outside the areas that see increased rainfall.

That is one reason forecasters and climate scientists pay close attention not only to whether El Niño forms, but also to how strong it becomes and how long it persists. A stronger, longer-lasting event can increase the odds of pronounced regional extremes, including drought conditions that intensify because warmer air can increase evaporation and stress landscapes and water supplies.

Hurricanes: less favorable Atlantic conditions, but no guarantee of safety

El Niño can affect tropical cyclone formation, particularly in the Atlantic. On the U.S. East Coast and Gulf Coast, one commonly cited effect is that El Niño makes it harder for hurricanes to form in the Atlantic Ocean. As a result, El Niño years often coincide with less severe Atlantic hurricane seasons.

But scientists caution against interpreting that tendency as protection. It only takes one major storm making landfall to cause catastrophic damage. In addition, climate change has caused temperatures in the Atlantic to soar, which provides more fuel for storms that do form. In other words, even if the atmosphere is somewhat less conducive to development overall, the ocean can still supply substantial energy to any system that does organize.

It is also important to note the geographic limits of El Niño’s influence: it does nothing to temper storms that form in the Pacific. For communities and decision-makers, that means the overall risk picture depends on basin, season, and local vulnerability, not just on whether El Niño is present.

What to watch as the forecast window approaches

With forecasters placing the odds of emergence between June and August at 62%, the coming months are likely to bring heightened attention to indicators in the tropical Pacific. El Niño is defined by a combination of ocean temperature patterns and atmospheric behavior, including the weakening of trade winds that allows warm water to shift toward the Americas.

As the event develops, the questions that matter most for impacts are the same ones scientists are already raising: How strong will it become, how long will it last, and how will it interact with the already-warmed climate system? Swain’s comment that the evidence is still early underscores that forecasts can evolve as conditions in the ocean and atmosphere become clearer.

Why this matters for planning, not just curiosity

El Niño is sometimes treated as a seasonal talking point, but the stakes are practical. A strong event can raise global temperatures, influence the likelihood of heat waves, and shift precipitation patterns in ways that affect agriculture, water management, and disaster preparedness.

At the same time, the pattern’s effects can cut in different directions. In some places, increased rainfall and cooler temperatures can reduce drought pressure and wildfire activity; in others, the extra heat can contribute to more severe drought. In the Atlantic, hurricane formation may be suppressed on average, yet the risk of major damage remains because a single landfalling storm can be catastrophic and warmer ocean temperatures can intensify storms that do develop.

Ultimately, El Niño is best understood as a powerful natural fluctuation that now operates within a climate system that has been warmed by human activity. That combination helps explain why recent years have produced record heat and why forecasters and scientists are watching the Pacific closely as summer approaches.

Key points at a glance

• NOAA’s latest official forecast projects a 62% chance that El Niño develops between June and August and persists through the rest of the year.
• El Niño occurs when trade winds weaken, allowing warm ocean water to move from the Eastern Pacific toward the Americas.
• A strong El Niño can raise average global temperatures; the hottest years on record generally occur in El Niño years.
• Recent record warmth in 2023 and 2024 coincided with a long, strong El Niño pattern that helped shatter global temperature records.
• Scientists emphasize that human-caused global warming is the main driver of the long-term warming trend; even without El Niño, last year ranked among the top three hottest years on record.
• Regional impacts can include shifts in rainfall and temperature, with the Southern U.S. often seeing more rain and cooler conditions.
• One year of wetter weather may not be enough to replenish reservoirs in the drought-stricken Southwest, according to the National Integrated Drought Information System.
• El Niño can make Atlantic hurricane formation less likely on average, but it offers limited protection; it only takes one major storm to cause catastrophic damage, and warmer Atlantic waters provide more fuel for storms that do form.
• El Niño does not temper storms that form in the Pacific.