Winter: Not-so-cold facts

December 2011 got off to a balmy start, and that was a clear indicator of what was to come as last winter ended up being the fourth-warmest on record in Philadelphia.

The difference between the first few days of last December and this one is that December 2012 has come on considerably warmer.

Last year, the average temperature for the first four days was 44; the Dec. 1-4 period this year will come in over 50 as the daily high makes a run toward 70. Yesterday's high of 67 was one shy of the record for the date.

No seriously wintry weather is imminent, or on any reasonably visible horizon.

The Climate Prediction Center has the odds favoring warmth into at least mid-month, with upper-air high pressure camped over the East to repel wintry storms.

Accu-Weather's monthly forecast posts daily high temperatures above normal for 17 of the first 20 days of December.

It is impossible to predict when the balminess might end, but if anything last winter proved that the atmosphere can defy the astronomical calendar.

The entire cool season passed without a single cold snap -- defined by National Weather Service climate specialist Mark DeLisi as three consecutive days of temperatures failing to get above 35.

In fact, Philadelphia hasn't had a cold snap, by that definition, since the three-day period that ended Jan. 24, 2011.

DeLisi looked at the last 62 winters and identified six as having passed without a single cold snap.

Five of those have occurred during the last 22 years. But that is not to say that one will become the sixth in the last 23 years.