THE FLOORBOARDS WERE cold and the sky was clear. Birds twittered and chattered as the day dimmed, but the gray was a false alarm, or at least a premature one. One tiny patch of snow, no bigger than the discarded water bottles nearby, survived along the curb. Fended off by the mask and the hat, the cold settled for attacking the earlobes. The 10-year-old tried going barefaced and bareheaded, but covered up after two crosstown blocks. The produce shelves outside the grocery markets were emptied out or else guarded by transparent barriers. Vapor coming up from the mask condensed out into the eyebrows; what felt like the first flake of snow was just a droplet falling from the brow to the nose. When the real flakes came they were hard to see against the dark, but they hit an outstretched hand with a palpable little “paff.” The dusting of snow that stuck to the railings quickly washed away, and the night was full of the dripping and gurgling of ordinary rain.