Change the days and times displayed
Calendar has several options for customizing how many days and hours are shown. You can customize Week view to show all seven days of the week or just Monday through Friday. You can customize Day and Week views so that the Calendar window shows from 6 to 24 hours of events per day, and you can mark when your day starts and ends.
Choose Calendar > Preferences, click General, then choose from the pop-up menus.