The extraordinary cooling of surface waters in the tropical Pacific conitinues to wane, but its effects on worldwide temperatures were evident in March.

Last month ended up as the coolest March in 12 years, based on NASA satellite micro-wave sounding data released this afternoon.

It also marked the second consecutive month of temperatures below 30-year averages, the first time that's occurred since July and August of 2008.

In fact, when February 2008 finished ever-so-slightly below normal it ended an 18-month run of above-average temperatures.

The March temperature was 0.18 degrees Fahrenheit below the 30-year average, said Dr. John Christy of the University of Alabama, keeper of the data.

As might be expected, the tropics were especially cool, about 0.6 degrees Fahrenheit below normal.

The El Nino, which had surged into the "strong category" has been weakening, and the government's Climate Prediction Center expects it to fade altogether by June.