Winter doesn't officially arrive for three more weeks, if we base our definition on astronomy. But many meteorologists consider winter to be the three coldest months of the year. And that would make tomorrow, December 1, the beginning of "meteorological" winter.

In the coming month, the average daily high slips from 49^oF tomorrow to 39^oF by New Year's Eve, with the average daily low falling from 33^oF to 24^oF. That's no surprise, given the shortness of daylight - nearly every December day has less than nine and a half hours.

An average December's snow is about three and a half inches, but there's a wide variation from year to year. Of the last 100 Decembers, more than a third have had an inch or less, while a handful have had 10 inches or more.

Here's something to keep in mind as we head into December: nine of the last ten Decembers were warmer-than-average, with below-average snow. So even an average December will probably seem cold and snowy simply because of what we have to compare it to in recent years.