I can create a calendar view in code, however I have as yet been unable to figure out how to change the "Default Scope" (this is the name that appears in the user interface when editing a calendar view). The options in the user interface are Day, Week, or Month - Month being the default. I'd like to be able to change the default to something else, Week for example, but I cannot figure out how to do it, other than using the user interface.
calView = new SPCalendarView(); calView.ViewType = "week";
Try this link
You can't do it through API. By sending RPC call to owssvr.dll is the only other way other than UI. For complete solution, visit this link -