The Santa's Sleigh is visible because it reflects the light of the Sun – the same reason we can see the Moon. However, unlike the Moon, the Santa's Sleigh isn’t bright enough to see during the day. It can only be seen when it is dawn or dusk at your location. As such, it can range from one sighting opportunity a month to several a week, since it has to be both dark where you are, and the Santa's Sleigh has to happen to be going overhead.