I work in a non tech driven city and I'll say a lot of the academic based companies lean towards python. Most likely because it's the language they were taught on in school. I will say that a lot of the more hungry companies that are a bit more lean use node. I know a handful that use clojurescript and the rest are either php and ruby with some sort of npm stack controlling the front end.
I could imagine sf to be a lot more node heavy though given that they take the technical stack a bit more serious than other companies. Uber for instance uses node, but the job available in my area required a python understanding. I can see it trickle into more jobs as the education of the benefits of node bubble up to management and the availability of a javascript workforce becomes more present.