No one else is awake, and therefore there are less distractions.
At night, there is this endless feeling. There is no rush to begin or end. The night just falls later and later. At moments the night is just much more relaxing.
With a son in a nearby room sleeping, there is a better chance that he won’t wake up at night compared to 5 or 6am.
I can work anytime of the day, but I’ve always had an attachment with working through evening.
It’s more important to not wait until the mood strikes you, but to get done what you set out to do.