It all depends on the Moon or if it rained the night before.
I never go out in darkness or return in darkness. The best
time I have found is after a hard rain. It could be 8:00am
and they are still returning to bed. We have barometers to
check the pressure. The best pressure is 30 and dropping.
There will be more movement at these pressures. If you
don't have one, checkthe dragon flies. When they fly low to
the ground, the pressure is high and it's getting ready to rain.