Context

As per the update from NOAA’s Climate Prediction Center, it appears a La Niña has developed for the second year in a row. The latest La Nina is expected to last through the early spring of 2022 (February).

What is Double-dip?

• Two La Ninas happening one after the other (with a transition through ENSO neutral conditions in between) is not uncommon.
• It is usually referred to as a ‘double-dip’. In 2020, La Nina developed during the month of August and then dissipated in April 2021 as ENSO-neutral conditions returned.

Understanding the geographic phenomenon

• La Nina (means ‘little girl’ in Spanish) is a natural ocean-atmospheric phenomenon.
• It is marked by cooler-than-average sea surface temperatures across the central and eastern Pacific Ocean near the equator.
• El Nino: It is the opposite of El Nino(meaning ‘little boy’), that is marked by warmer-than-average sea surface temperatures across the central and eastern Pacific Ocean near the equator.

	La Nina (Little Girl)	El Nino (Little Boy)
Precipitation	La Nina causes an increase in precipitation. It also causes formation of low-pressure areas.	El Nino usually causes a decrease in precipitation and has been found to cause drought-like conditions in India.
Wind strength	Trade winds are even stronger than usual, pushing more warm water toward Asia.	Trade winds weaken. Warm water is pushed back east, toward the west coast of the Americas.
El Nino Southern Oscillation (ENSO) cycle	A part of the El Nino Southern Oscillation (ENSO) cycle.	A part of the El Nino Southern Oscillation (ENSO) cycle.

*ENSO is characterized by opposing warm and cool phases of oceanic and atmospheric conditions in the tropical Pacific Ocean.