First of all, let me make this perfectly clear: this was a wonderful Christmas for me and my family. There were no disasters, no tragedies. It was the second Christmas without our mom, and that sadness looms over everything, but the memory of her love offsets it.
No, the darkness this year was not a metaphor, not an abstraction. It was a literal, if weird, darkness.
In part it's something I noticed when I've been out and about at night: Far fewer houses are lit up for the holiday. I observed this in Wilkes-Barre, and it made me wonder if all the dark houses are also vacant, since they seemed not to have lights on of any sort. Even in my neighborhood, houses that used to be garishly lit up are dark, or have much more subdued displays. This year the night is not filled with the sound of blower motors keeping inflatable Santas and Grinches and snowmen inflated. Laser projectors no longer play across the faces of houses - my mom was often delighted at the stray light points that trespassed onto our house and yard from the neighbors' projector across the street. On the drive out to my brother's house Christmas Eve, I noticed that many of the houses that were reliably lit up year after year were now dark. (To be fair, several that had previously not been worthy of note were lit up elaborately this year.)
It also seemed like the roads themselves were darker, as if half the streetlights had gone out. I don't know if this is really the case. Nanticoke's Main Street was completely undecorated, though this may be related to the recent replacement of streetlights throughout the downtown. The schools in Nanticoke were also missing a holiday display of any sort. (Patriots' Square has the city snowflake decorations hanging around it, and the traditional Christmas Tree is on display.)
But the weirdest aspect of the darkness was the sky. The sky itself seemed unusually dark. The Moon was not scheduled to rise until about 2:00 AM as a waning crescent, so its absence was understandable. But there were no stars showing, nor even bright Venus in the Western sky or Jupiter in the East. This could have been explained by clouds, of course. But there was none of the usual skyglow, no reflection of lights off the clouds, which should have been made worse by the presence of snow on the ground reflecting any downward-aimed lights into the sky. (Thanks to a minor snowstorm the weekend before Christmas and sustained cold temperatures, we actually had a White Christmas this year, though it all melted by December 27.) All these factors combined to have an effect like a black fog permeating the area, blotting out anything beyond some close radius.
My Christmas lights remain lit, and will stay lit for as long as I feel like lighting them. At least until New Year's Day, perhaps until the Epiphany, or Russian Christmas, or Candlemas Day. The days have been growing longer since the Solstice on the 21st, but I am in no hurry to darken the lights of Christmas.