Google does not only deduce your location from your connection. It keeps data on you. If for example you have some residual information (cookies etc.) on your

Google does not only deduce your location from your connection. It keeps data on you. If for example you have some residual information (cookies etc.) on your browser or you've logged in to your account, google will probably continue to show your last location known by it. Google might even query local devices as you suggested, who knows? It is really aggresive on getting location data.