The Monday through Sunday workweek normally lasts eight working days, and the Monday through Saturday playweek normally lasts 4 working days. When you add in the possibility of public holidays, that total quantity increases to 10 working days, and twelve-playing days.
But the days themselves are simply one element of the calendar, and there are plenty of others. The months of the calendar represent different seasons, and the time between each of those months offers us the seasonal cycle. At the start of spring, the temperature 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 unique time related to it, and the calendar helps us track all of those shifts. Any seasonal change is reflected in the calendar, and it tells us when and where to go during specific times of the year.
Image source: free-printable-calendar.com