Every month University of Alabama in Huntsville climatologists John Christy and Roy Spencer report the latest global temperature trends from satellite data. Below are the newest data updated through March, 2012.
U.S. Hits Record Highs in March: Iowa is the "warmest" place on Earth
Global climate trend since Nov. 16, 1978: +0.13 C per decade
March temperatures (preliminary) baseline: 30-year average for the month
Global composite temp.: +0.11 C (about 0.20 degrees Fahrenheit)
Northern Hemisphere: +0.13 C (about 0.23 degrees Fahrenheit)
Southern Hemisphere: +0.09 C (about 0.16 degrees Fahrenheit)
Tropics: -0.11 C (about 0.20 degrees Fahrenheit)
February temperatures (revised):
Global Composite: -0.11 C below 30-year average
Northern Hemisphere: -0.01 C below 30-year average
Southern Hemisphere: -0.21 C below 30-year average
Tropics: -0.28 C below 30-year average
(All temperature anomalies are based on a 30-year average (1981-2010) for the month reported.)
Did you experience an unusually warm March? The UAH press release explains that you were not alone if you live in the lower 48 states:
Compared to seasonal norms, March 2012 was the warmest month on record in the 48 contiguous U.S. states, according to Dr. John Christy, a professor of atmospheric science and director of the Earth System Science Center at The University of Alabama in Huntsville. Temperatures over the U.S. averaged 2.82 C (almost 5.1° Fahrenheit) warmer than normal in March.
The previous U.S. record warm anomaly in the 33-year satellite temperature record was in November 1999, when temperatures over the U.S. averaged 2.22 C (about 4° F) warmer than the seasonal norm for November. The next warmest March was in 2007, when temperatures over the U.S. were 2.0 C (about 3.2° F) warmer than normal.
While the long-term climate trend over the U.S. has seen warming at the rate of about 0.21 C (almost 0.38° F) per decade during the past one third of a century, March's temperature anomaly is just that: an anomaly, Christy said. "We see hot and cold spots over the globe every month, and this was just our turn. A one-time anomaly like this is related to weather rather than climate. Weather systems aligned in March in a way that changed normal circulation patterns and brought more warm air than usual to the continental U.S."
In fact, the warmest spot on the globe in March (compared to seasonal norms) was northeastern Iowa, where temperatures for the month averaged 6.20 C (about 11.2° F) warmer than normal.
By comparison, the winter (DJF) of 2011-2012 averaged 0.94 C (about 1.7° F) warmer than seasonal norms for the continental U.S.
In recent years March has not typically seen temperature extremes over the U.S. The March 2011 temperature for the "lower 48" was at the seasonal norm.
The coolest spot on Earth in March 2012 was northwestern Alaska, where temperatures averaged 3.89 C (7.0° F) colder than normal.
Go here for the satellite temperature data.