Global sea surface temperatures reached 20.97°C in March, the second-highest on record for the month, the Copernicus Climate Change Service said. The reading was the hottest for March since 2024 during the last El Niño. It signals a likely transition toward El Niño later this year. The shift can amplify heat extremes on an already warming planet.
The World Meteorological Organization said the recent La Niña is expected to give way to neutral conditions before swinging into El Niño later in the year. Scientists warn that oceans absorbing most excess heat are fueling stronger storms and rainfall. They are also driving coral bleaching and thermal expansion that contributes to sea-level rise.
Seasonal outlooks now hinge on that shift taking hold in the coming months. The Climate Prediction Center said El Niño could appear as soon as May, with a 61% chance it forms at some point between May and July of this year, USA Today reported.
A super El Niño
The National Oceanic and Atmospheric Administration in the United States assigned a 25% chance that El Niño could strengthen into a super El Niño by fall or early winter, according to the Mirror.
That classification is generally linked to warm Pacific anomalies of at least 2 degrees Celsius and has been seen only five times since 1950. The last occurrence was in 2015–2016. “An El Niño is not a storm. It does not affect you directly. It is a cycle that contributes like many other factors to produce weather changes and sometimes extremes,” said AccuWeather Long-Range Forecaster Paul Pastelok, according to the Mirror.
“We will likely see at least a moderate El Niño, but more likely a strong El Niño,” said AccuWeather Senior Meteorologist Chad Merrill.
A stronger El Niño raises the risk of impactful storms later in the year. It can drive unseasonably warm spells and periods of heavy rainfall in the United Kingdom.
El Niño often disrupts Atlantic hurricane formation by strengthening upper-level westerly winds that can shear apart nascent storms. Forecasters caution that regional windows of favorable conditions can still produce dangerous cyclones. The CSU outlook calls for about 75% of the average hurricane activity observed from 1991 to 2020, USA Today reported. It assigns probabilities for a major hurricane making landfall of 32% for the entire US coastline, 15% for the US East Coast including Florida.