climate change and supply reliability (continued)
The El Niño condition occurs when the temperature is above normal in the eastern Pacific Ocean near the equator. When the temperature is lower than normal, the La Niña condition occurs. When the temperature is normal, the condition is called Neutral. During fall and winter, El Niño normally brings 30-40 percent more rainfall. La Niña brings less rainfall during fall and winter. El Niño brings cooler temperatures during fall and winter; La Niña is warmer. Florida also gets few Atlantic hurricane landfalls during El Niño years. During the last century, 11 out of 12 major freezes in central Florida occurred during Neutral phases.
The El Niño or La Niña condition seems to return in the range of two to seven years. The tropical Pacific is Neutral at least half of the time. El Niño or La Niña each occur about a quarter of the time. Each El Niño, La Niña, or Neutral year begins in October and ends in the following September. Knowing the sea surface temperature in the tropical Pacific Ocean can help predict the climate conditions for the coming year.