A consensus bulletin from the World Meteorological Organization, normally every three months, with the chances of El Nino, neutral and La Nina.
Forecasts and bulletins
The WMO combines forecasts from its Global Producing Centres for seasonal prediction and other major centres, plus expert judgement, into one bulletin. It is issued every three months, with extra updates when things change fast.
It gives probabilities rather than a single number, and it is what many national weather services (including in Southeast Asia) refer to.