Research has found that, controlling for team quality, National Basketball Association visiting teams win more often when playing to the east of their home time zones and less often when playing to the west. We reaffirm this finding for 1991-2002. We find that only these seasons’ day games, and not their far more frequent night games, featured a significant relationship between time zone and visiting team win probability. We hypothesize that some of these day-game effects were biological in origin. The 2002-2013 seasons featured no significant relationship between time zones and visiting team win probability for either day or night games.