El Niño is a periodic event characterized by the appearance of warm water off the coast of Peru, leading to significant ecological and economic impacts. Klaus Wyrtki presents a new theory explaining the occurrence of El Niño, which is not due to weakened southeast trade winds but rather to strong southeast trade winds in the central Pacific two years prior. These strong winds intensify the subtropical gyre and the South Equatorial Current, increasing the east-west slope of sea level in the western equatorial Pacific. When the wind stress relaxes, accumulated warm water flows eastward, likely in the form of an internal equatorial Kelvin wave, leading to the accumulation of warm water off Ecuador and Peru and a depression of the thermocline. El Niño is thus the result of the equatorial Pacific Ocean's response to atmospheric forcing by trade winds. The theory explains the onset of El Niño and the first temperature peak, while the second peak may be related to the surge of the North Equatorial Counter Current. The paper discusses various aspects of this theory, including the relationship between wind stress, sea level, and temperature, and provides insights into the complex dynamics of El Niño.El Niño is a periodic event characterized by the appearance of warm water off the coast of Peru, leading to significant ecological and economic impacts. Klaus Wyrtki presents a new theory explaining the occurrence of El Niño, which is not due to weakened southeast trade winds but rather to strong southeast trade winds in the central Pacific two years prior. These strong winds intensify the subtropical gyre and the South Equatorial Current, increasing the east-west slope of sea level in the western equatorial Pacific. When the wind stress relaxes, accumulated warm water flows eastward, likely in the form of an internal equatorial Kelvin wave, leading to the accumulation of warm water off Ecuador and Peru and a depression of the thermocline. El Niño is thus the result of the equatorial Pacific Ocean's response to atmospheric forcing by trade winds. The theory explains the onset of El Niño and the first temperature peak, while the second peak may be related to the surge of the North Equatorial Counter Current. The paper discusses various aspects of this theory, including the relationship between wind stress, sea level, and temperature, and provides insights into the complex dynamics of El Niño.