Part of these pages have been reproduced on "SPOCK'S PAGES"
It has been estimated that the Vulcan calender was established approx. 943 Vulcan Years after the catastrophe caused by the solar flare (Spock's World, Diane Duane). The length of the year was first established as 252 sunrise to sunrise cycles, especially as due to the axial tilt being small (see below) their day/night length is roughly equal ( except at the poles). Due to the lack of seasonal changes the year was arbitrarily divided into equal time spans of 12 blocks (VuM) which each consisted of 21 VuD, although there is a loose connection between the 21 VuD cycle and the orbit of T'Khut and Vulcan round each other. This connection is also reflected in the name of the middle month, when T'Khut is at its nearest to Vulcan. There are no weeks on Vulcan and therefore no Week-ends as such. However, most Vulcans do take time to spend in other pursuits than "Work" (such as extended meditation, mental-games etc) usually every 10 days.
Vulcan is 0.56AU (astronomical units) from its Sun: Star 40Eri (52,360,000 miles). This means that the tidal (gravitational) effects are greater than those found on Earth from its sun.
The near perfect circular orbit of Vulcan round its sun (see Spock's World Diane Duane) and the small axial tilt means that Vulcan has no real seasons.
As Vulcan is closer to its sun the orbit is smaller and the year is shorter than that of Earth, Vulcan orbits its sun in 252 Vulcan days (VuD) The VuY is devided into 12 equal units (T'Kuhati) of 21 VuD's each
One rotation of Vulcan about its own axis is 18 Vulcan Hours (VuH) know as V'hral (approx 25.3 Earth hours (EH)).
1 VuY = 252 VuD = 266.4 Earth Days (ED) = 0.73 Earth Year (EY)
1 VuM = 21 VuD = 22.2 ED = 0.79 Earth Month
1 VuD = 18 VuH = 25.3 EH = 1.058 ED
1 VuH = 54 VuMi= 84.3 EMi
1 VuMi = 1.41 EMi
1 VuMi = 54 VuS
The month names stem from well before The Reformation (Surak's time). It is actually one of the most complete records of the most ancient Vulcan. The names have been kept, throughout Vulcan history even when the calender calculations had changed to become more precise and "logical".
