May on fire. Waiting for the Super El Niño?

This was not simply an early taste of fine weather: meteorologists are openly describing it as an exceptional, anomalous and historically significant event. There is also another development, perhaps even more worrying, looming on the horizon: something major is brewing over the oceans - a phenomenon known as Super El Niño, which could make the summer of 2026 one of the hottest on record. To understand why it is so hot, we need to look at one of the best-known forces in weather patterns: the anticyclone. An anticyclone is an area of the atmosphere where air pressure is high. In these conditions, air tends to sink from higher altitudes toward the surface and, as it descends, it compresses and warms. The result? Clear skies, no rain and, often, very high temperatures. The anticyclone that has swept across Europe in recent days is not the usual kind we see in summer. It is a subtropical anticyclone of North African origin: in other words, a high-pressure bubble that formed between the Sahara, North Africa and the Atlantic Ocean, then pushed northward until it reached European latitudes. This system helped trigger an intense heatwave that is highly unusual for the month of May. The temperatures recorded in recent days would not be extraordinary in July or August. But in May, when the weather is usually still cool and sunny days alternate with rainy ones, they are completely out of the ordinary. It is as if someone had suddenly skipped two months on the calendar The data speaks for itself - and it is striking. In Spain, some areas reached 42°C, with Seville already exceeding 38°C the previous weekend. In France, temperatures set new all-time records for the month of May. In Italy, the situation is not very different. In the north, especially across the Po Valley, thermometers reached 36-37°C. In Moncalieri, not far from Turin, the weather observatory of Collegio Carlo Alberto, active since 1865, recorded an all-time maximum temperature record for the month on 26 May: 37.6°C, surpassing the previous record of 36.5°C set in 2009. A 160-year historical record, shattered in a single day. The most affected Italian cities were given a so-called red alert by health authorities: Bologna, Florence, Rome and Turin. A red alert is the highest heat warning level, and it means that conditions are dangerous even for healthy people - not only for vulnerable groups such as the elderly, young children or people with existing health conditions. In the United Kingdom, a country historically less accustomed to high temperatures, the national weather agency issued yellow warnings across many counties. Across the continent, more than 100 weather stations broke their own maximum temperature record for May - a figure with no precedent in modern European weather records.

A “heat dome” is a weather phenomenon that resembles a lid placed over a pot full of hot water. The air inside the pot becomes extremely hot because it is trapped by the lid.

Something similar is happening over Europe: meteorologists are describing a real “dome of hot air”, an atmospheric structure in which the anticyclone blocks air circulation, prevents cooler air from moving in from the north, and forces air masses to remain stuck in place for days. Under this dome, the sun keeps heating the land, while no cooler air arrives to bring relief. In recent days, temperature anomalies - the extent to which temperatures differ from the historical average - have been 8-10°C above normal, with peaks of 12-14°C in parts of France and England. In places where temperatures at the end of May are usually around 22°C, thermometers have reached 34-36°C.

So far, we have been talking about a local heatwave, linked to a specific atmospheric system. But another, much larger phenomenon is also underway - one that involves the planet’s oceans. It is called El Niño, and it is one of the most powerful and widely studied climate phenomena on Earth. To understand what El Niño is, we need to take a short journey into the Pacific Ocean. Normally, between Asia, Australia and South America, steady winds known as trade winds blow across the Pacific, pushing warm surface waters westward. This mechanism keeps the ocean in balance: cold water from the depths rises near the coasts of South America - a process known as upwelling - and the global climate remains stable. Every so often, however, this balance breaks down. The trade winds weaken or change direction, and warm waters are no longer pushed westward. As a result, huge amounts of warm water build up in the central and eastern equatorial Pacific, raising sea surface temperatures far above normal. This is El Niño. The name, which in Spanish means “the boy” or “the Christ Child”, was given by Peruvian fishermen centuries ago because the phenomenon tended to appear around Christmas, bringing unusual rainfall with it. Not all El Niño events are the same. Some are weak, some moderate and some strong. Scientists speak of a Super El Niño when temperatures in the equatorial Pacific exceed reference values by at least 2°C for at least three consecutive months. It is the most intense and potentially most devastating version of the phenomenon. The latest data from the ECMWF - the European Centre for Medium-Range Weather Forecasts, based in England and regarded as a global benchmark for climate forecasting - show that temperatures in the equatorial Pacific are rising increasingly sharply. According to experts, the likelihood of a Super El Niño developing in the coming months is extremely high: some estimates put the probability of an event of this intensity by autumn 2026 at more than 75 NOAA, the United States’ oceanic and atmospheric agency, indicates at least a 60% chance that El Niño will emerge in the coming months, with a one-in-three possibility that the episode will become “strong” between October and December.

El Niño is not a local phenomenon: it is a global disruptor. When it becomes active, its consequences are felt around the world, although in different ways depending on latitude. In the Americas, it brings drought to the Amazon and torrential rainfall to Ecuador and Peru. In Australia, it increases the risk of devastating droughts and major wildfires. In tropical regions, it disrupts the Asian monsoon. And average global temperatures tend to rise, because El Niño releases enormous amounts of heat stored in the ocean into the atmosphere. For Italy and Europe, the direct effects are somewhat less pronounced than in other parts of the world. However, El Niño interacts with the African anticyclone and the Azores anticyclone - the two major “taps” of European summer heat - amplifying their intensity and persistence. An event of this kind raises global temperatures and increases the risk of intense weather events. ECMWF seasonal forecasts indicate that the summer of 2026 will almost certainly be warmer than average, with temperature anomalies of between +1°C and +2°C compared with historical averages in several parts of Europe. For Italy, this would mean more frequent heatwaves and temperatures consistently above normal: July and August could bring peaks of up to 2°C above the already very hot average of recent years. Experts, however, are urging caution. In the summer of 2026, El Niño will probably still be in the early stages of development, with its most disruptive effects likely to emerge mainly in autumn and winter. Researchers at Columbia University also point out that it takes time to recharge the Pacific’s “heat battery”, and that it is somewhat surprising to see a new El Niño so soon after the 2023-2024 event. This suggests that global warming caused by human activities may be shortening the natural cycles of this phenomenon.

Anomalous heat in May, a possible Super El Niño on the way, record-breaking temperatures in some of the longest historical datasets: is all this just coincidence, or is there a thread connecting these events? For climatologists, the answer is clear. Climate change does not directly “cause” every single heatwave. But it creates the conditions for these events to become more frequent, more intense and longer lasting. When an extreme event occurs, such as an out-of-season subtropical anticyclone, it is already starting from a higher temperature baseline - and therefore reaches levels that would have been impossible in the past. The late-May 2026 heatwave would probably not have been as extreme in a world that was not already around 1.3°C warmer than in the pre-industrial era. And El Niño is layered on top of this background warming, pushing the system into increasingly unfamiliar territory. This late-May 2026 heatwave will pass, as all heatwaves do. Temperatures will fall, thunderstorms will arrive, summer will move on. But the numbers will remain there, in the historical records, showing that something has changed.