Today, 3 January 2016, is New Years Day on Mars. We have decided that today is a new year on Mars in part because it is the Winter Solstice in Mars’ southern hemisphere (Summer Solstice in the northern hemisphere,) and in part because we are about to launch our first invasion of the Red Planet, which begins a new era for Mars.
Because the marking of time and the creation of a calendar are human needs, we are establishing the Mars calendar using orbital benchmarks that serve the needs of human occupation of Mars.
The calendar begins with the Winter Solstice in each hemisphere, meaning that the first six months (referred to as “Sur”) will coincide with the winter/spring of the southern hemisphere AND will also be the summer/fall calendar for the northern hemisphere. Likewise, the Winter Solstice in the northern hemisphere will begin the final six months (referred to as “Nor”) of Year One AND will also coincide with summer/fall seasons of the southern hemisphere.
Today is the first day of the month of Sur One. We have kept the weeks at seven days and started the calendar on a Sunday; however, because Mars days are between 37 and 39 minutes longer than Earth, Mars will fall behind one day every 36 Earth days.
Our calendar for Mars has 12 months representing one orbit around the Sun, but since Mars takes almost twice as long to orbit the Sun, the months are much longer than an Earth month.
Unlike Earth, we have divided the calendar into three month groups that actually coincide with the two solstices and two equinoxes, therefore, the Mars calendar actually follows the seasons.
However, because the orbital speed of Mars and distance traveled is not uniform through the entire orbit, the four seasons each have a different number of days. This means Sur winter months have about 60 days each, Sur spring months are about 48 days, Nor winter months are about 52 days, and Nor spring months are about 65 days long.
For more information and to see the full Mars calendar go to the Mars Calendar page.