Global Temperature Trend Update: September 2011

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 September, 2011.

Global climate trend since Nov. 16, 1978: +0.14 C per decade

September temperatures (preliminary)

Global composite temp.: +0.29 C (about 0.52 degrees Fahrenheit) above 30-year average for September.

Northern Hemisphere: +0.31 C (about 0.56 degrees Fahrenheit) above 30-year average for September.

Southern Hemisphere: +0.27 C (about 0.49 degrees Fahrenheit) above 30-year average for September.

Tropics: +0.18 C (about 0.32 degrees Fahrenheit) above 30-year average for September.

August temperatures (revised):

Global Composite: +0.33 C above 30-year average

Northern Hemisphere: +0.32 C above 30-year average

Southern Hemisphere: +0.33 C above 30-year average

Tropics: +0.16 C above 30-year average

(All temperature anomalies are based on a 30-year average (1981-2010) for the month reported.)

Notes on data released Oct 5, 2011:

September 2011 was the fifth warmest September in the past 34 years — fifth warmest globally and in both hemispheres, 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.

Although last winter's La Niña Pacific Ocean cooling event has faded and a new one appears to be forming, the tropics continue to be warmer than seasonal norms: Last month was the seventh warmest September in the tropics.

Go here for the monthly temperature data sets.