Scripps Institution of Oceanography

Hey! What is an "SST Anomaly"?

Sea Surface Temperature anomalies in degrees Celsius, or "SST anomalies" for short, are how much temperatures depart from what is normal for that time of year. This makes sense; we might say that we had a "warm winter" even though it was still much colder than summer. What we mean is that it was warmer than a normal winter; in our parlance, we would say that it was a "positive anomaly". An unusually cold winter would be a "negative anomaly". For Pacific SST, an anomaly in the range of 1.5 to 3.5 degrees Celsius would be considered characteristic of an El Niño; the warmer and more widespread the water, the stronger the El Niño.


Last modified: 25 June 1997
Copyright © 2000 David W. Pierce. All rights reserved.