This might sound strange, but when I am stopped at a traffic light, I think of "Silver Bells" and "even stop lights blink a bright red and green" comes to mind. When I received supplies for my classroom at the beginning of school, the red and green construction paper was always deliberately stored with the white. The smell of the cedar trees outside our church immediately transports me not only to Christmas, but to the simpler times of my childhood. So does the smell of tangerines and oranges. Some others mentioned overcast weather, and I agree. When hurricanes were "in season" off the coast of NC, the Piedmont would become chilly and gray, reminding me of winter and Christmas. And when I smell wood smoke and piles of fallen leaves, I think "Thanksgiving" and Christmas! I guess you could say that Christmas is so often on my mind and in my heart that it doesn't take much to be put into the Christmas spirit!