In these days we are returning to speak of The Niñathe atmospheric phenomenon that could cause extreme weather eventslike storms or lightning floods, during the next autumn and winter season. It is an opposite oceanic and atmospheric phenomenon to El Niño and capable of causing intense weather effects due to decrease in temperature of the surface waters of the Equatorial Pacific Ocean.
In fact, according to the projections of the Noaa (National Oceanic and Atmospheric Administration, The US Federal Agency that deals with the monitoring of the oceans and the atmosphere), the surface waters of the Pacific Ocean they are cooling Quickly: this could indicate consequences globally, from an increase in rainfall in Southeast Asia to colder and more rigid winters in Europe.
However, it must be specified that the Niña it has nothing to do with the bad weather arriving on Italy in next dayswhich will instead be caused by an Atlantic depression that will cross the peninsula between Tuesday 9 and Thursday 11 September, causing instability above all on the central-northern regions and locally intense rainfall, in some cases above 100-150 millimeters.
What is Niña and what the effects are
As mentioned, Niña is a phenomenon characterized by a Anomalous cooling waters of the equatorial peaceful ocean, that is the opposite of what happens with El Niño, which instead involves a heating of the superficial ocean waters.
Together, El Niño and Niña are part of a wider climatic scheme, called El Niño-Southern Oscillation (Ensse). Specifically, Niña occurs when the Pacific surface records temperatures lower than 0.5 ° C Compared to the average, in a period of at least 5 months.
The problem is that this temperature anomaly does not produce effect only in the surrounding areas, but also in the rest of the world: This imbalance, in fact, alters global atmospheric circulation, moving winds and currents globally. In particular, during Niña atmospheric circulation decreases, doing increase pressure superficial on the equatorial peaceful (at the height of French Polynesia) and lowering it in the western sector, near Australia. In the same way, the normal transport of hot water From east to west it intensifies, favoring the lowering of ocean temperatures.
The projections of the WMO on the impact of La Niña
According to the projections of the Wo (World Meteorological Organization), in the period September-November 2025 there is a probability of 55% That the surface temperatures of the Pacific Ocean cool down: if instead we look at the quarter of October-December 2025, the chances that the Niña influence the climate of the entire planet rise to 60%. For the moment, therefore, it is not certain that Niña will occur by the end of this year.
In general, however, this phenomenon tends to have a strong impact on the United States, where it causes cold and rainy winters in the northern states and a warmer and more sodious climate in the south of the country (in states such as Texas And Florida). At the same time, the effects of this atmospheric phenomenon also fall on Latin America, Australia and Africa, as well as on Asia, where Niña causes further strengthening of monsoon.
Despite being further away, Europe could also undergo effects, with more rigid and unstable winters and a greater probability of extreme events such as storms and lightning floods.
The Niña, however, it has nothing to do with the bad weather arriving on Italy in next dayswhich will instead be caused by an Atlantic depression, in this moment present in the west of the British Isles, which will head towards the Western Mediterranean and cross the Peninsula between Tuesday 9 and Thursday 11 September, bringing conditions of instability and bad weather especially on the central-northern regions, where locally intense rainfall is expected and in some cases higher than 100-150 millimeters.
