Moving beyond "ultra-strong," the "strongest" El Niño is expected to continue this winter.

The Korea Meteorological Administration (KMA) stated that the El Niño that began in May is anticipated to become the "strongest El Niño on record."

El Niño is officially recognized as having begun when the 3-month moving average of sea surface temperatures in the El Niño-La Niña monitoring region of the tropical Pacific remains 0.5 degrees Celsius (0.9 degrees Fahrenheit) higher than normal for five months or more.

According to the KMA, the sea surface temperature in the El Niño-La Niña monitoring region from October 11 to 17 was 30.0 degrees Celsius (86.0 degrees Fahrenheit), which was 3.3 degrees Celsius (5.9 degrees Fahrenheit) higher than normal.

A deviation of 1.5 degrees Celsius (2.7 degrees Fahrenheit) or more from normal is classified as a "strong El Niño," meaning this baseline has been significantly surpassed.

The deviation from normal sea surface temperatures in the El Niño-La Niña monitoring region was 2.6 degrees Celsius (4.7 degrees Fahrenheit) for October and 2.4 degrees Celsius (4.3 degrees Fahrenheit) based on the August–October moving average.

The KMA explained that this is the largest deviation since records began in 1950, surpassing the records set during the strong El Niño events of 1997 and 2015.

El Niño occurs when the trade winds (easterlies), which normally push warm surface water in the tropical Pacific toward the western Pacific, weaken. As a result, the warm surface water accumulated in the western Pacific spreads to the central and eastern Pacific, raising sea surface temperatures in these regions and creating an energy circulation pattern different from usual.

El Niño is not a consequence of climate change and is a "natural" phenomenon, with official records dating back to 1881.

However, it affects global weather and also fuels global warming.

El Niño typically strengthens in the winter, and the current El Niño is projected to peak in December.

The KMA forecasted, "Sea surface temperatures in the El Niño-La Niña monitoring region are expected to remain high, developing into the strongest El Niño on record."

When El Niño occurs, convective activity in the tropical western Pacific weakens, and anticyclonic circulation frequently develops in the Philippine Sea and to the east of South Korea.

Consequently, warm and humid southerly winds ride along the edge of this anticyclonic circulation into the country, resulting in higher temperatures and increased precipitation.

At the Korean Meteorological Society conference last month, a research team led by Professor Kuk Jong-seong of Seoul National University stated that during strong El Niño development years—1982/83, 1997/98, and 2015/16—precipitation in November, the El Niño development period, was more than double that of an average November.

In its 3-month outlook released on October 23, the KMA predicted that temperatures in November and December would be higher and precipitation greater than normal, while for January of next year, temperatures would be higher than normal and precipitation similar to normal.

However, the KMA emphasized, "Winter weather is influenced by various climatic factors in addition to El Niño, such as sea surface temperatures in the Indian and Atlantic Oceans, Arctic sea ice, and Eurasian snow cover, so the latest forecasts should be checked."

(Photo: Yonhap News)