When it gets a bit too warm here in the Southwest desert to hike during the day I turn to night hiking. Sometimes I even freehike, which is to say without benefit of clothing. I have done it a few times now, most recently the night before last. It was still in the Nineties, but with no sun and a breeze it was quite comfortable. Plus, I was guaranteed not to see anyone else as it was after midnight!
My only concerns are nocturnal critters, which in the desert means mostly rattlesnakes and scorpions. In fact, almost the only times I have seen snakes in this particular hiking area near my home, which I have hiked dozens of times, is at night.
And this time I saw two smallish rattlers at different locations along the side of trail. One was curled up waiting for a mouse or other prey, but the other one was stretched out and moving, which I almost never see. I leave them alone and they reciprocate.