The World Meteorological Organisation has said there is a 75-80% chance of weak El Niño weather conditions developing in the East Central Tropical Pacific region over the next three months.
Sea surface temperatures in the region have already reached levels consistent with a weak El Niño, said the WMO, but the corresponding atmospheric temperatures have not yet materialised.
The El Niño/Southern Oscillation (ENSO) is a naturally-occurring phenomenon that can have a major influence on weather and climate patterns over many parts of the world.
The last El Niño - which was of far greater strength - occurred in 2015-2016.
It was linked with droughts, flooding and coral bleaching in different parts of the world.
A weak El Niño such as the one now predicted for the next three months could significantly affect rainfall and temperature patterns in many regions.
Maxx Dilley, director of WMO's Climate Prediction and Adaptation branch, said it could have important consequences for the agricultural and food security sectors, and for the management of water resources and public health in many parts of the world. he said it could may also combine with long-term climate change to boost 2019 global temperatures".
Weather model predictions of the strength of the forecast El Niño range from just a warm-neutral condition through to a moderate strength El Niño event, with sea surface temperatures peaking at approximately 0.8 to 1.2 degrees Celsius above average.