If we look at nature, there are many animals that are nocturnal, the opposite of the diurnal human lifestyle.
The intermediate crepuscular schedule (twilight activity) is also common. There are some reasons for this.
1. A form of niche differentiation, where a species' niche is partitioned not by resources but by time itself
2. Keeping out of the heat of the day
Other animals, like cats, rabbits and mice, have the behavior of sleeping partly during the daytime and partly during the night (metaturnal).
I read a Taoist Text in which the timing was discussed briefly, which stated that "The Tao does not have bad timing."
Some people say that the hour of Tzu (11 PM - 1 AM) and Wu (11 AM - 1 PM) ar the most auspicious times for practice. These are the periods when yin and yang energy begin the waning and waxing.
But this does not mean that practice at other times would not be successful.