Here is the typical forecast for San Francisco (city) during the summer months (mid June through August): "Fog at the coast in the morning, clearing at mid day, returning in the late afternoon/evening." Every.single.day. LOL. It's a wonder they pay those meteorologists in the summer months. So, if you want "clear" photos, your best bet would be 2-3 pm. If you want the iconic fog rolling in photo, maybe 4-5 pm. Morning, the entire bridge could well be shrouded in fog and you'd see nothing.