In my experience, the time of day doesn't matter as far as the mental aspect goes, but I've noticed that the visuals I get from DXM are highly variable depending on the current light level. At night in a dimly lit area, the (open eye) visuals tend to shift around a lot, forming Aztec-like structures, circuitry, and alterations to the features of the place I am looking at. They are very bright, but often incoherent. The ones I get when I close my eyes toward a bright light source are very sharp and sustained. They move at various speeds and their movement can be controlled. They tend to be more three dimensional, and perfectly clear. These are the types that run like physics simulations.
This variability is what makes DXM one of the more interesting substances, in my opinion.
