The current El Nino weather phenomenon is expected to strengthen before the end of the year and to peak between October and January, the World Meteorological Organization said on Tuesday.

Climate models and experts suggest surface waters in the east-central Pacific Ocean are likely to be more than 2 degrees hotter than average, potentially making this El Nino one of the strongest since 1950, following similar weather events in 1972-3, 1982-3, 1997-8.

El Nino is the warm phase of the El Nino Southern Oscillation (commonly called Enso) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (between approximately the International Date Line and 120 deg W), including off the Pacific coast of South America.

El Nino is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific.

Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected.