Oh man, how could I choose?
I love tripping at any time of the day, but each time is quite different from the others. For the sake of simplicity, I will only discuss day and night, leaving out all the subtle variations.
I've tripped by far the most at night, simply by chance; I happen to have the most opportunities to be alone then, and thus, the most opportunities to trip (as I don't really have anyone around me who likes to trip like I do). Tripping at night has generally proven to provide the most profound experience. Perhaps this is because the general atmosphere at night is more ominous, more danger-filled, more mysterious and unknown. That energy really permeates a trip. It doesn't have as much of an impact when you're inside, but if you're outside in the wilderness at night, you start to feel like a frightened animal sometimes. Although this can be difficult at times, it also unlocks the doors to some unique aspects of the human, mammalian, and reptilian psyche. I also get much more colorful visuals at night, and much more noticeable.
Day tripping, on the other hand, is generally infused with a sense of wonder and glee and mischief, heavily reminiscent of childhood. I would only ever want to trip outside in nature during the day. Tripping inside would make me feel gross and just make me long for the outdoors. The visuals I get outside in the sunlight are much different from the ones I get inside or in the dark. They consis of heavy magnification of what I'm looking at and incredibly complex, fractallized patterns emerging from the organized chaos of nature, such as through the ruslting leaves of a forest. Forests are definitely my favorite places to be while tripping, followed very closely by mountains. Or forested mountains, better still! I get a much greater sense of communion with nature during the day, and I always feel embraced with absolute love and joy. I've had some very profound and unique experiences outside during the day on psychedelics, but there's a certain edge missing from it that makes each trip more likely to be a fun, recreational, refreshing trip into the land of childhood and nature spirits, rather than a deep, powerful, world-shattering introspective trip.
So, you see, they're both wonderful