NOAA: For 1st Time, US Records 16 Straight Months Of Above-Avg. Temps; 9/11-9/12 Period Warmest Ever

NOAA’s latest State of the Climate roundup shows that September marked the 16th month in a row with above-average temperatures for the lower 48 states of the U.S. Both the calendar year and the 12-month period from October 2011 through September 2012 were the warmest on record, and statistics show that it will require an unusually cold October through December period for 2012 to rank anything other than the warmest year.

The U.S. has never before recorded 16 straight months of above-average temperatures, and although natural variability has also played a role, the warmth this year is consistent with long-term trends related to global warming.

Over the month, the mercury averaged 67°F, which is 1.4°F higher than the long-term average. The April-September period, which is considered the “warm season” in the continental U.S., was the warmest on record, with an average of 68.2°F (the runner-up is the 1934 warm season, at 67.6°F).

EDIT

Although September by itself was only 23rd warmest such month on record (tied with 1980), the unusual warmth from January through August virtually guarantees that 2012 as a whole will be the warmest since modern recordkeeping began. According to the National Climatic Data Center (NCDC), October through December would need to rank among the top 10 percent coldest such periods on record to thwart the warm temperature record. (Globally, however, 2012 is not expected to rank as the warmest year, as the January to August period ranked ninth on the list.)

EDIT

http://www.climatecentral.org/news/september-bookends-the-warmest-12-months-on-record-noaa-15094