Yes, that is snow on the roof. It was only October when I shot these photos but it seemed unseasonably frigid under the perfectly clear sky that night. My GPS can be made to measure temperature when placed in diagnostic mode. I did this, and set it on a fence post while this shot exposed. I returned to find it displaying 16 degrees below zero. A year earlier I was still shooting in November, in comfortable temperatures well above freezing. I suppose anything can happen this late in the year.