The changes in sea surface temperature patterns over a year reflect the warming and cooling trends known as seasonal change. The changes are directly related to which latitudes receive the most direct rays of the sun and the longest periods of daylight. Can you think of other variables that change with respect to latitude over the course of a year?

Over longer periods of time, sea surface temperature patterns also show shifts in longitude. Some years, a large body of warm water moves from the western Pacific Ocean eastward to the west coast of South America. This shift in ocean circulation affects global atmospheric conditions and can result in increased flooding, droughts, and damaging hurricanes. This occurrence is known as El Niño.

  !   Click the image to play the animation. Examine the animation frame by frame to look for months when El Niño is occurring.

If you want to confirm your observations, click here for a listing of El Niño events. The chart summarizes sea surface temperatures along the equator between 150° W and 180° W. The water temperature for each season is categorized as strongly cooler than normal (C+), weakly cooler (C-), neutral (N), weakly warmer (W-), or strongly warmer (W+).