I believe it's open from sunrise to sunset, though I've never tested either.
Parks hours are sunrise to sunset.
Park is open 24hrs, says so here on this site.
Sunrise to sunset, but there are no barriers to access after hours.
Sunrise to sunset, though you should be gone by last light.
There isnt a direct answer, but they say sunrise to sunset! So your best guess is around 8:30 to 9:00
Thanks! Your answer is awaiting moderation.