An El Niño that began to form last fall has matured and is now fully entrenched across the Pacific. Changes in sea surface temperatures, or SSTs, brought about by an El Niño affect the atmosphere, resulting in distinctive changes in the rainfall pattern across the Pacific Basin. These changes show up as anomalies or deviations in NASA’s analysis of climatological rainfall. This map shows sea surface temperature (SST) anomalies for the Pacific Basin, shown as degrees Celsius above or below average. Credit: NOAA Climate Prediction Center. In a typical El Niño, warmer than average SSTs off of the...