Here in S.Calif, Fuerte has always been one of the most popular and best tasting avocados, comparable to Hass. For some reason, I haven't seen Fuerte fruit in the stores for the last few years. But the trees are easy to find at nurseries and big box stores.
I have a seedling Fuerte in a container and a store bought Fuerte I planted this past spring. They can take the occasional 28F that I get, and if they can handle mid 20's F they should survive here. But I don't think I'd plant a Fuerte if 15F was common every few years. I'd be looking for some Duke seeds (which I am anyways) since Duke trees grow in a town just north of Oroville, Calif where it's a lot colder than where I live.