Despite a very cool November in Philadelphia, 2012's temperature will still set a record for warmth across the whole of the calendar year. Our yearly temperatures through the end of November are running nearly four tenths of a degree over 2010 and nearly nine tenths of a degree over the prior warmest year (including December) on record, 1931.
Official climate data in Philadelphia goes back to 1872 on a monthly basis.
We won't finish the year over the 60 degree mark for an average and likely won't finish over 59 degrees for the year, but given that the warmest year in our climate record was 58.10 from 1931, we're likely going to blow past that by a solid margin given our warm start this December.
2010, which had been leading the pack for the first 11 months of the year, had a December temperature of nearly five degrees below average and consequently did not finish as the gold standard in temperature.
Out of the nine warmest years on the data set listed above, seven of them are since 1990 with 1921 and 1931 the only years that do not fit that data set. December 1931 was the 2nd warmest on record and headlined the warmest winter on record in Philadelphia history that carried into 1932. Our December probably does not end up as warm as 1931 but it will likely finish above average and help push us to the finish line as the warmest year in Philly's 140 year climate history.
Nationally, 2012 will likely end up as the warmest year on record as well.