We go to Fort Funston on the Pacific Ocean in the morning.
There are tall dirt cliffs along the ocean and it is a long walk down a steep hill to get to the beach.
If the tide is moderately high, there isn't much beach.
In addition, San Francisco's "treated" sewage line (ick!) blocks walking along the beach when the tide is high.
So, we try to only go to the beach when the tide is low.