National Overview - September 2012
Warmest 12-month consecutive periods for the CONUS

« National Overview - September 2012


Warmest 12-month consecutive periods for the CONUS

These are the warmest 12-month periods on record for the contiguous United States. The October 2011-September 2012 12-month period marked tied June 2011-May 2012 as the third warmest consecutive 12-months that the contiguous U.S. has experienced and the warmest October-September period on record. In addition, during the June 2011-September 2012 period, each individual month of the 16-month period ranked among the warmest third of their historical distribution for the first time in the 1895-present record.


Warmest 12 months

Rank Consecutive 12-month Period Temperature Departure
(from 20th Century Average)
Warmest August 2011 — July 2012* +3.34°F
2nd Warmest July 2011 — June 2012* +3.29°F
3rd Warmest October 2011 — September 2012* +3.25°F
4th Warmest June 2011 — May 2012* +3.24°F
September 2011 – August 2012* +3.24°F
6th Warmest May 2011 – April 2012* +2.88°F
7thWarmest November 1999 – October 2000 +2.69°F
8th Warmest April 2011 – March 2012* +2.67°F
9th Warmest October 1999 – September 2000 +2.64°F
10th Warmest September 2005 – August 2006 +2.56°F
11th Warmest August 2005 – July 2006 +2.54°F
12th Warmest September 1999 – August 2000 +2.53°F

* – Preliminary Data