:-)

Sounds like Dresden is mixing up magic and science. Because that's a logical explanation...until you start to think about it.

The full moon, technically, is a specific instant, and in at least half of the world that instant is going to happen in daylight...but I don't know any lore that has werewolves changing during the day (unless it's a 'verse where they can change at will). So the sight of the moon is significant. How significant...is the interesting question.