Blame Charles Dickens or Irving Berlin or legions of unheralded marketing geniuses, but the association of snow with Christmas remains as durable as it is improbable for most of the nation.

Around here, the snow season typically doesn't ripen until deep into January, and for sound climatological reasons.

Our big snows are produced by coastal storms that draw in moist air from the Atlantic, and this time of year when water temperatures are in the low 40s, onshore winds are apt to import mild air, which means rain.

About 90 percent of all December precipitation in Philadelphia has fallen as rain.

The chances for snow on Christmas Eve or Christmas Day actually are quite small. In the 41-year period from 1919 to 1960, not a micron of snow was measured officially in Philadelphia on those days.

On occasion, however, conditions align just right (or wrongly, depending on one's perspective), and such was the case in 1966.

Snow began during the early morning hours of Dec. 24 and intensified late in the day, depositing about a foot by the first moments of Christmas Day. The snowfall remains a Philadelphia record for a Dec. 24.

We feel reasonably safe in predicting that we won't see a repeat this year, and the odds against it happening again in any other year are formidable.

But cold reality has night been able to ice the poetical links between snow and Christmas. Where would Santa be without his sleigh?

Charles Dickens added a healthy dash of snow to his wonderful Christmas Carol, and it's possible that he saw his share of snow around Christmastime, giving that he lived near the end of the end of the so-called Little Ice Age.

In the 20th Century, Irving Berlin and a crooner named Bing Crosby forever cemented the snow-Christmas relationship with the song, White Christmas.

Appropriately, song opens with "I'm dreaming." In most years, that's about as close as we'll come to snow on Christmas.