6:00 pm – 6:30 pm
when conditions allow, i.e. when temps are >50°F, Dew Point >45°F, Heating Degree Days <9, atmosphere stable, no pressure drops, no strong wind, no rain in the area
But bats will be hunkered down to try and survive the freeze for the next several days

Sunset: 5:51 pm
Dark: 6:21 pm (10-20 minutes earlier if cloudy)
Sunrise: 7:28 am