The hottest it's ever been in SF was 103 degrees which occurred on June 14, 2000 and July 17, 1988. I was visiting SF for the 1st time on that July 17th/'88 day. Last summer it got pretty hot for a week or two, and with the fires up north clogging the air with smoke it was pretty uncomfortable. Two weeks ago it got really hot for a couple days but maybe around 90. Having lived on the coast (Pacifica) for 17 years - it may get hot for a few days but if it's really hot inland (and it does get very hot there) the fog gets sucked in to cool things off. Also, it always cools down at night.