The Old Calendar

The Old Calendar was developed before the Fourth Reckoning by the Valaran Empire. It spread across Kaabara and eastern Cuyania centuries before the Fourth Reckoning and is still in use by my cultures to this day.
The calendar divides the 372-day year into 12 months of 31 days each. Every month has 3 weeks, which are 10, 11, and 10 days long. The calendar begins with the autumn equinox. Autumn then lasts for 4 months, followed by three months each of winter and spring, and then 2 months of summer. These are not exact to the season - the spring equinox is actually a few weeks into spring because winter is longer than spring, but these are the traditional divisions of the year.