Tree hierarchy:
The Site tree object occupies the next highest level in the hierarchy below that of the Project tree object. A site contains buildings. All building components exist inside it.
The Site object, when selected, provides an entry point to the site data on the Properties For: Site dialog. Here, you can view information about the site location, modify atmospheric and climate data such as the climate and moisture zone associated with the site as well as solar correction factors. There is also terrain data which includes information about monthly ground temperatures and soil type. Finally, if applicable, options to set daylight savings start and end dates.