Cherry beach (lifeguard station at left) was quiet, nice, and a little too full of cigarette butts, lurching labradors and goose poop. But we wrote the couple's name in the sand, had a simple ceremony, and watched the sunset across the channel. Much cooler than the city.
For a fancier early morning, consider Rosetta McClain park on the bluffs - there's a nice tree/sward area (above right), or the view over the cliffs. you'll have to book it for a full wedding, but you could zip in early for a morning elopement, I expect. The City website says hours are "dawn to dusk everyday". hmmm