Check stargazing conditions for the night.
Stargazing quality is best expressed as limiting magnitude — the faintest star you can see, where higher numbers mean darker skies. The Bortle scale sets the baseline, from about magnitude 8 under pristine skies down to 2 or worse in a city centre. Moonlight is the largest variable you can actually plan around, since a full Moon costs nearly two magnitudes and wipes out most deep-sky observing regardless of how dark your site is. Humidity scatters light and softens contrast above about 55 percent. Airmass matters too: a target 20 degrees up is viewed through nearly three times the atmosphere of one overhead, which is why patience for an object to rise pays off.
Limiting magnitude
Mag = 8.0 - 0.62 x (Bortle - 1) - 1.9 x moon fraction - humidity penalty - airmass penalty
Airmass
Airmass = 1 / sin(altitude)
Because it is brighter and it scatters across the whole sky. A full Moon raises sky brightness by nearly two magnitudes everywhere, so it can turn a dark rural site into the equivalent of a suburban one. Serious deep-sky observers plan around the new Moon window for precisely this reason.
Airmass is how much atmosphere you look through, relative to straight up. At 90 degrees it is 1.0; at 20 degrees it is nearly 2.9, which means far more scattering, absorption and turbulence. Waiting for a target to climb above about 30 degrees makes a visible difference.