I will say that I enjoy riding my bike in the wee hours of the morning during summer here. The wind isn't howling, there's very little traffic on the streets - so your life is in less danger, it's cool rather than hot out, and with everything quiet, you can hear any cars approaching from a long distance. There seem to be less dogs running loose, too. So it's a good way to get some exercise and enjoy a more relaxing, leisurely ride.
Of course, among those folks who are out at that time, there's a higher percentage of drunks, and ne'er-do-wells. And you sometimes hear folks having domestic disputes through their open windows. But again, on a quiet bicycle, you can hear anyone or anything approaching from a good distance.
Of course, when folks see me riding at 03:00 or so, they probably assume that it's ME who is up to no good! I have gotten to know the newspaper delivery folks in the area. That seems to be when they're out making their rounds as well!