El Nino originally referred to the annual warm current off western Peru. It was named after the Christmas child El Nino de Navidad because the phenomenon began in late December.

El Nino now usually refers to the more severe weather conditions that occur every three to seven years when the ocean currents off South America are so warm as to cause a reversal in climate conditions in the east and west Pacific regions. Where there would normally be lots of rain, there is drought and rainfall is high where it is usually scant.

Australians and New Zealanders would be familiar with the term. El Nino is blamed for unusually dry conditions. South East Asia, India and southern Africa are also affected.

At the same time South America experiences arid conditions. In Peru and Ecuador El Nino has economic effects as the normally abundant fish life is depleted by the warmer waters off the coast.

The opposite of El Nino is often referred to as La Nina, or little girl. High rainfall in Australia and New Zealand are blamed on La Nina.