In Gene Roddenberry's novelization of The Motion Picture he indicated that nine Vulcan seasons were equal to 2.8 Earth years. This would make Vulcan's 年 456 ± 33 Earth days long.
Vulcan "has no moon", so it is unknown what portion of a 年 is represented 由 the "month" of Tasmeen. The novelization of The Motion Picture could be read to imply that Vulcan's "months" are whole seasons.
更多 information
link
