The technical rule is you can be there till dark, i don't know how well this is inforced but do know of someone who got a ticket for being out after dark at the park.
Maybe 8pm
Till about 9pm. Then the park rangers take you out
Not really sure sorry
Until dusk
Dusk. That's applies to all nyc parks
Your allowed to stay in the BBQ area until dusk.
9pm
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