There is an 80 per cent chance of the warming El Nino phenomenon developing between June and August, increasing the risk of extreme weather events, the World Meteorological Organization said on Tuesday.“Fuelled by unusually warm ocean waters in the tropical Pacific, El Nino conditions are developing and are set to influence global temperature and rainfall patterns,” the United Nations’ WMO weather and climate agency said.Forecasts from the WMO global network “indicate a pronounced shift towards El Nino conditions, with probabilities reaching 80 per cent for June-August”, the Geneva-based organisation said.El Nino is a natural climate phenomenon that warms surface temperatures in the central and eastern equatorial Pacific Ocean, bringing worldwide changes in winds, pressure and rainfall patterns.It typically takes place every two to seven years and lasts around nine to 12 months. Conditions oscillate between El Nino and its opposite La Nina, with neutral conditions in between.The likelihood of El Nino developing by November is “near or above 90 per cent”, and most forecast models suggest it will be “at least moderate – and possibly strong”, the WMO said in its quarterly El Nino/La Nina update.