Could cars from San Francisco be more prone to rust than cars from Silicon Valley/interior?

San Francisco gets a lot of regular fog. Rolls in from the ocean every day. Silicon Valley and other interior areas don’t get the fog and are much drier in general. Do you think cars stored and driven in San Francisco would be more likely to suffer from corrosion?

Yep. Humidity and salt spray are great for encouraging corrosion. However, this is not nearly as much of a problem as it used to be. Cars have a lot more corrosion protection than “back in the day.”

The rust protection on cars is much better now, as stated. It addresses the tons of salt and calcium chloride dumped on roads in the winter around the Great lakes (Rust Belt) and the North East. The salt spray in San Francisco is peanuts compared to this.

Having said that, yes a S F car would be somwhat more rust prone than one from the Silicon Valley area.

This is chiefly a speculative question since neither area is particularly noted for taking a toll on cars. Although we might imagine a slight edge to SF for rust-producing ability, cars from both areas will eventually die off from old age long before rust becomes a factor. If you are seriously car shopping, the home location of your cars of interest can be disregarded as irrelevant.

Around what model years did corrosion protection significantly improve?

Mid 80’s was the MAJOR turning point.

That’s why GM (Fisher Body Division) choose Syracuse University to do a MAJOR study in the early 80’s on car rust and prevention. And why every major manufacturer has taken this study and applied the results to their cars.

Rust protection was legislated in 1976 first in Canada as a result of the “Rusty Ford” Class Action lawsuit and shortly after that in the US where rust through warranties became law. Since that time both metals and coatings have improved, and cars no longer need additional after market rustproofing, such as Ziebart. Cars without a rust warranty cannot be sold in Canada or the US.

The last rust bucket I had was a 1976 Ford Granada, which rusted even with an aftermarket treatment.

Both San Francisco and the Silicon valley are not very rust-prone, and I would only have hangups buying a car from around the Great Lakes and the North East.