The strongest El Nino to date is coming to an end, as recent trade winds have cooled the surface of the Eastern Pacific Ocean since late May, the Meteorological Agency said.

"Although it is hard to say when the phenomenon ends, El Nino will not come back," said Kazunobu Nakamura, head of the agency's El Nino Monitoring and Prediction Center. El Nino is the term used to describe a phenomenon characterized by extensive warming of the ocean's surface in the tropical Eastern Pacific lasting several seasons. It causes a disruption of weather patterns over many parts of the globe.

According to the center, trade winds around the equator -- the key factor in relieving the phenomenon -- were extraordinarily weak in April but grew stronger in May. The wind moved the warm surface water of the Eastern Pacific westward, causing deeper, colder water to rise to the surface, the center said.

Wide areas of surface water around the equator reached temperatures of more than 28 degrees in early May. But these areas have diminished, and some surface water has cooled to about 26 degrees. In early May, most surface areas were warmer than normal, but by the end of the month, some had actually become cooler than normal. "It will, however, take a while for water temperature to affect the atmosphere," said Kenichi Yuda, a weather forecaster at the agency. "Also, because the effect on Japan is indirect, Japan's weather will not see a dramatic change right away."

The current El Nino is the strongest ever, with ocean surface temperatures rising 3.6 degrees higher than normal. The phenomenon has caused extraordinary weather all over the world, including an abnormally warm winter in Japan.