California’s seasonal weather is influenced by El Niño and La Niña – temporary climatic conditions that, depending on their severity, make the weather wetter or drier than normal.

El Niño and La Niña episodes typically last 9 to 12 months, but some may last for years. While their frequency can be quite irregular, El Niño and La Niña events occur on average every two to seven years. Typically, El Niño occurs more frequently than La Niña, according to the National Oceanic and Atmospheric Administration (NOAA).