The El Niño weather event is expected to gain in strength before the end of this year, according to the World Meteorological Organization (WMO).
In its latest update, the WMO says the 2015 occurrence will be among the three strongest recorded since 1950.
Severe droughts and significant flooding in many parts of the world are being attributed to this El Niño.
The WMO warn these impacts are likely to increase and this event is now in "uncharted territory".
El Niño is a naturally occurring weather episode that sees the warm waters of the central Pacific expand eastwards towards North and South America.
The phenomenon, which happens every two to seven years, usually peaks late in the calendar year, although the effects can persist well into the following spring.
This year's El Niño seems to be following that pattern.
According to the WMO, the peak three month average water surface temperatures in tropical Pacific will exceed 2C above normal.
It is the strongest event since 1998 and is expected to be among the three most powerful ever recorded.