San Jose has hugh variance. Alviso along the bay is very low chill, but Almaden where I’m at, gets 800+ chill hours most years. This year, I’m probably at 1200 chill hours!
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Santa Clara Valley used to be the area for growing cherries.
Our microclimates are weird. The parts by the Valley don’t get enough chill like @bleedingdirt noted. There were some citrus orchards around North San Jose/Alviso. There is one even now. Quite close to my place. A huge grove of Navel oranges surrounded by Google and Cisco buildings 
The stonefruit orchards are deeper inland. Never by the coast or by the Bay.
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I feel like avocados are highly adaptable . Here’s a 30 footer in London. Yes…London. 50 degrees North. And it’s loaded. May well be the northernmost avocado tree
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Keep in mind, that’s growing in the heart of the urban heat island, an area that is basically zone 10a or at least 9b, surrounded by brick walls and concrete. But yes, it’s an interesting tree and in terms of latitude, it’s probably the northernmost regularly fruiting outdoor, unprotected avocado tree.
I am in touch with someone growing avocados near the English coast south of London, and he’s planning to try grafting that tree to one of his trees. His biggest tree is a Hass seeding that’s 5 years old, so not even particularly hardy. That London tree may also not be particularly hardy, in light of its protected microclimate.
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This tree is in Lafayette and seems to be quite productive.