It's hard to phrase this since I'm doing it at another's behest. I suppose the question is, does When is the darkest time of day? warrant being a question separate from Does natural light affect sneaking?? Despite my protest at kotekzot's edit, I admit that it was worthy of being asked first. Lawton also makes a good point that the question as kotekzot has rephrased it may be a duplicate. The way that it isn't a duplicate is that it is not asking whether light affects sneaking but whether natural light fluctuates.
My excuse for if this post seems hastily written is because close votes are starting on the first question, so I feel pressured. I'm considering opening up another meta-question to tackle the "duplicate" accusation more directly.
I rephrased the title to be more general. These are terms that I came up with, so if anyone knows better technical terms, suggestions are welcome.