sure exactly when that specific day occurs this year. Somewhere around
December 10 Boston experiences its earliest sunset. The days continue
to shorten because the sun rises later and later in the morning until
December 21, when the winter solstice occurs. Then you can break out
the Mannheim Steamroller albums and also avoid those people who try to
diminish Christmas by pointing out the pagan origins of its calendar
date.
Unseasonably warm weather is good for business but if it is dark when 
people get out of work they go home.  It doesn't matter if its fifty 
degrees or thirty degrees.  If its light out they are much more likely 
to do something besides return to their burrow.  So the tide has now 
turned and the afternoon light will remain a few seconds  longer.  A 
good part of the city's population is beginning to leave for the 
holidays.  Harvard students come back for reading period and then leave 
again.  Many MIT students return for Independent Activity Period in 
January but the spring semester doesn't formally begin until February 
6,2007.  Harvard's spring semester begins January 31, 2007.  Then its 
St. Patrick's Day, Groundhog Day, the packing of the Red Sox luggage 
for spring training in Florida, and late winter storms.  Eventually 
spring comes, even to Central Square.  The City of Cambridge begins 
monthly street cleaning on April 1.