Which ocean is most affected by El Niño?

Arab Weather - The ocean most affected by the El Niño phenomenon is the Pacific Ocean, especially its eastern tropical part. During El Niño, water surface temperatures rise abnormally in this region, leading to major changes in weather patterns worldwide. El Niño affects rainfall and temperatures, causing drought in some areas such as Australia and Indonesia, while leading to heavy rains and floods in other areas such as the west coast of South America.