I would say anytime before 9am if you live in the suburbs. I have mower up until dark, but only because I sometimes work late.
As in the time of day? We get dewy here. So, too early, before the sun hasnt dried it, wet grass cuts unevenly. Too late, same problem.
Usually after the grass is dry. But already 7:40 a.m. our neighbor is cutting his. Way too early.
Too early, too late? There is only one answer to fit both'of'em... When you are dead! Too early to rise up and hava a revenge on the lawn... Too late to have a revenge on the lawnower.
Going by noise restrictions where I live ... between 8am and 10pm is okay.
As long as you don't think people are sleeping, then is there a too early or too late? As long as you have enough light as well.