El Niño and La Niña are two opposing climate patterns that occur in the equatorial Pacific Ocean and can have global impacts on weather, ecosystems, and economies. They are part of the broader El Niño-Southern Oscillation (ENSO) cycle, which refers to the irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean. Here are some key points about El Niño and La Niña:

• El Niño: This is the warm phase of the ENSO cycle, characterized by above-average sea-surface temperatures in the equatorial Pacific Ocean. During El Niño, trade winds weaken, and warm water is pushed back east, toward the west coast of the Americas. El Niño can have global impacts on weather, including droughts, floods, and hurricanes.

• La Niña: This is the cold phase of the ENSO cycle, characterized by below-average sea-surface temperatures in the equatorial Pacific Ocean. During La Niña, trade winds are even stronger than usual, pushing more warm water toward Asia. La Niña can also have global impacts on weather, including droughts, floods, and hurricanes.

• ENSO-neutral: This refers to conditions when sea-surface temperatures are at or near average, and neither El Niño nor La Niña develops.

Episodes of El Niño and La Niña typically last nine to 12 months, but can sometimes last for years. They occur every two to seven years, on average, but they don’t occur on a regular schedule. During El Niño, increased precipitation is expected in California due to a more southerly, zonal, storm track. During La Niña, increased precipitation is diverted into the Pacific Northwest due to a more northerly storm track.