After a high of 66 in Philadelphia today, we've had two straight days of 65 degrees or warmer in Philadelphia in late November. It's not uncommon to get such mild weather this late in the month -- since 1998, we've had temperatures of 65 or higher on 19 occasions during the latter third of the month...a lil more than once per year on average. The fact that it gets above 65 in late November isn't cause for winter concern, however, given the fact that we've seen a mixed bag of results overall in past years regarding winter chill and late November warmth.
Some years, such as 2001, had four days of 65+ degree warmth and also had a couple of 70 degree days thrown in for good measure. You might recall that 2001-2002 was one of the warmer winters on record and one of the least snowy as well in Philadelphia. However, 2003-2004 was a pretty cold one in Philadelphia although snowfall was somewhat pedestrian (18" for the winter), yet that late November featured three days of this type of mildness in the city.