Earliest sunsets in SF: last night and tonight, at 4:49:44 pm. Tomorrow's will be two seconds later.
"But Jef," you ask, "it's not the solstice yet. How does that work?" I'm glad you asked! The solstice is the shortest day, but the earliest sunset and the latest sunrise are offset from it in opposite directions because the Earth's orbit is slightly elliptical. Sunrises are still getting later by about a minute per day. They will continue getting later at a slowing pace until January 4th/5th.