Again, I'll second OlSarge here. I was out with my dog a little while ago wearing my Harris tweed jacket and a medium-weight flannel shirt, and I was still chilly!
I might mention that my family (on my mother's side) has been in the LA area since the 1870s. My great-great grandfather, Andy Francisco, founded the Los Angeles Daily Times in 1881. It later became the LA Times under General Otis. Francisco was later an LA County Supervisor. Francisco Street, just west of downtown LA, is named after him.
As to the matter of tweed getting you killed by gangs, I have heard of young men being bumped off (sometimes mistakenly) for wearing red in a Crips neighborhood or blue in a Bloods hood. So, it might be inadvisable to wear that blue Donegal tweed in a Bloods-controlled neighborhood. (Not much red tweed around, at least for men.) Fortunately, that sort of feudism among minority youth seems to have decreased considerably in recent years although there was a sad case the other day where a teenager with no known gang affiliations was shot for wearing the "wrong" color. In my own case, as an almost-septuagenarian "cracker," it is unlikely that the gang kids would mistake me for part of the opposition.