A single guard suffices, even though the nocturnal hours are slow and dismal.

The dark circles beneath his eyes gave testament to his nocturnal hours.

At first, people blamed the nocturnal hours kept by the market workers.

So it shouldn't be surprising to learn that some residents of this city actually spend their free nocturnal hours in Central Park searching for stars.

I got to the hospital during nocturnal visiting hours.

The nocturnal hours are especially bad, are they not?

And indeed, as the pleasant nocturnal hours passed, the numbness faded and strength returned.

The pits were noisy throughout the nocturnal hours.

I was nursing, and my son was still keeping nocturnal hours.

Wolves begin approaching human habitations, though limit their visits to nocturnal hours.