The first six months of 2011 are now in the books. Heat waves are currently in the headlines, but how does the national average temperature compare to other years and ‘normal’? And what does the first half of the year portend for the year as a whole?
The indication is that 2011 will mark the continued return of U.S. national temperatures to conditions much closer to the 20th century mean, down from the unusually elevated temperatures that characterized the 1998–2010 period.
If this proves to be the case, it strongly suggests that the unusually warm decade from 1998–2007, was just that–unusual–and does not best represent the expected trend or the climate state of the U.S. for the next several decades to come.
Background
The U.S. National Climatic Data Center has compiled a data set representing the annual average temperature for the contiguous United States which dates back to 1895.…