The Monday through Sunday workweek typically lasts eight working days, and the Monday through Saturday playweek typically lasts 4 working days. When you include in the possibility of public holidays, that overall amount increases to ten working days, and twelve-playing days.
But the days themselves are just one element of the calendar, and there are lots of others. The months of the calendar represent various seasons, and the time between each of those months provides us the seasonal cycle. At the start of spring, the temperature level is high and the days are warm, while at the end of winter the air is cold and the days are cold. Every season has its own special time associated with it, and the calendar assists us track all of those shifts. Any seasonal modification is reflected in the calendar, and it informs us when and where to go during specific times of the year.
Image source: free-printable-calendar.com