Detroit has a nice Riverwalk and I'm sure any locals can point to other local things of interest.
I will say that I was at a tech event in Detroit in the fall. Things I would do (knowing what I do about the city even today) in SF at night without a second thought felt risky and many other attendees felt the same--and there were some safety incidents. It wasn't even so much the things that might make you feel unsafe in the Tenderloin. It's that if you were walking 1/2 mile to someplace it was just deserted.
Uhmm, I don't think I agree here. The Mediterranean has better weather all around. I like mid-west weather more if we are talking about US. SF is also very windy. Annoyingly windy. SF weather is "okay" but nowhere near the best. It does have great scenery nearby though.
I just looked things up for SF and I have to say I would not regard it as some of the best in the world. Pretty temperate, with mild annual swings: summer highs of 23C and winter lows of 7C - that's actually a little on the cool side for me hah. But the rain is wrong way round, IMO wet summers and dry winters are better, and it seems like it's also quite humid?
My experience is obviously limited, and weather preference is subjective, so read the above as if it's coming from one idiot on the Internet.
Which, arguably, was more important 50 years ago.
Correction - places near SF have amazing weather. SF itself - not that amazing.
Compare the population decline of Detroit with Milwaukee:
Did you mean the Bay Area, or SF?
Most of the Bay Area has fairly nice weather year-round. San Francisco though, has pretty terrible weather. Foggy and cold most of the time.