I try to run every morning, wherever I am. I'm a much nicer person when I do. Ask anyone. And I generally run in Central Park, either the 6 or 4 mile loop or if it's hot or I'm just lazy, I take a quick 1.58 mile loop of the reservoir. I used to (10 plus years ago) run at night and occasionally now, for whatever reason I still do. Here are the differences between the two.
There are many more people, especially in the summer at night (especially around 7 PM).
The people at night tend to be younger, faster, and better looking than the people in the morning. And unless you have the maturity to run your own pace (which I do not), you tend to get a much better workout at night. More than that, a lot of them also seem interested in racing, which is fine. But if you're going to pass me, you're going to fucking earn it.
There seems to be much more dog shit in the park at night. And on a humid night like tonight, the park just reeks of it. Thanks, dog owners.
The sidewalks and streets going to and from the park are more crowded and the people on them don't seem to like runners. A boy (perhaps 12 years old) purposely hit me with his bike last week, forcing me to gently straight arm the little shit and gracefully vault a tree box. A junkie executed a perfect 180 degree turn in front of me last night, then veered the 30 degrees back to get in front of me as I tried to avoid her (netting 150 degrees) and screamed "if you hit me I'll hit you back" as I stutter-stepped to her right (my left). And the fucking livery cabs must get a bonus for hitting runners.
There are more rats and raccoons in the park at night. Hower, both coyotes (and I only actually witnessed the first hunt) were in the morning.