At first, it seemed as if Apple had only altered the look of the Calendar app in Mavericks with fake leather and stitches now all gone. However, few changes and feature additions make it for a more solid application overall now.
One of those additions is better time zone support for your events.
As before, you have the option to set a specific time zone for your events when you set their time and date.
What’s new is that Calendar now displays the event’s time zone above the little event name should you switch your calendar to another time zone. The latter you can still do by clicking on the small arrow next to the currently selected time zone in the upper right corner of the Calendar app.
For this to work, you need to have time zone support enabled in Calendar. To do that, go to the Calendar preferences (shortcut: ⌘ + ,) -> Advanced and check “Turn on time zone support”.