The warming El Nino weather phenomenon, which pushed global temperatures to record highs the last time around, is expected back in the middle of this year, the UN said Friday.

The United Nations’ weather and climate agency said El Nino conditions were likely as early as the May to July three-month window.

The World Meteorological Organization (WMO) meanwhile said early signs indicated a strong event.

El Nino is a naturally-occurring climate phenomenon that warms surface temperatures in the central and eastern equatorial Pacific Ocean. It brings changes in winds, pressure and rainfall patterns.

Conditions oscillate between El Nino and its opposite La Nina, with neutral conditions in between.