A message that wakes someone gets a complaint, not a reply. This applies to outreach and to any other automation: night is the most expensive time of day per message sent.
Why it costs more than it looks
It is not only irritation. An account working around the clock without pauses is unusual in itself: people sleep. Flat activity across twenty-four hours is a visible signal regardless of what the messages say.
Which window to set
Early morning to late evening, with a night pause. The exact hours depend on the audience: for shift workers the evening window can be wider.
It also helps not to run evenly inside the day: unbroken sending from nine to nine is also a rhythm people do not have.
Time zones
The main complication: your midnight is somebody's midday. A list collected from international chats can span seven or eight hours. Aim at the zone where most of them are, and narrow the window rather than widening it.
What to do with the queue
Move night messages to the morning rather than firing them a second after the window opens: a hundred messages at 09:00:00 is the same spike, just earlier. Spread them across the first hour.
The same elsewhere
Quiet hours are not only for outreach — comments and chat replies at night have the same effect — quiet hours for accounts.
How Neurogram does this
Everything above is manual work that runs into the number of hours in a day. Neurogram does it on your own accounts and without you: it collects channels and audiences, writes comments and replies with a language model, and keeps limits and quiet hours so the accounts survive. See pricing or look at your case.