There are 13 months in one year, each with 28 days. There are still 7 days in a week, and 52 weeks in a year. There is also one extra day, the Winter Solstice, that does not belong to any month, but marks the transition between years.
New Year Day - Winter Solstice (aka O’Witrah, Day of Witrah)
Fourth-Month - Day 7 is the Spring Equinox (aka O’Spralla, Day of Spralla)
Seventh-Month - Day 14 is the Summer Solstice (aka O’Somnar, Day of Somnar)
Tenth-Month - Day 21 is the Fall Equinox (aka O’Otone, Day of Otone)
The calendar was mathed and written out by Camlin Writes