Well, it is the beginning part of December before the solstice, so the weather can really go either way. The desert gets cold at night most of the year anyhow. By doing this so close to the solstice you compress the middle-of-the-day light so there is less waiting from the morning golden hour to the evening golden hour.
But something that is making my brain itchy... "followed by a moonlit night photography session led by a local Navajo guide." And the Navajo guide is mentioned a couple of more times. Is there a way to word that to have this sound a bit less racist?