While this cold shot, albeit brief, has been mightily impressive by November standards, it didn't quite crack the coldest days to average, ever, department. Just the fifth coldest day to average since 2010.
Keep in mind that "average" is relative-- and can change based on climate and temperature cycles, plus the increased size of the Philly metro adding a degree or two of warmth as time has progressed. That said, in a short sample size like a few years you can get an idea of what days tend to stand out as more impressively cold than others. All data is compared to the current thirty year normal cycle, which reflects data that was collected between 1981 and 2010.
|Coldest days to average, using 1981-2010 "normals" for high and low.|
Another point I want to make as well -- the temperatures themselves aren't all necessarily the coldest ever -- yesterday was the third coldest (tied with 1996) for this particular date. October 29th, 2011 (Anniversary of Snowtober) was the coldest high for that date on record, with the other dates safely above the cold thresholds of those particular days.