to commonly asked questions.

How do I adjust the time on my computer?

How do I change the date and time on my computer? My calendar times are incorrect.

Go to system preferences (under the black apple in the top left corner of your screen)

Be sure to check the "set date and time automatically"

Your computer will now pull your time zone based on your IP address and the dates should adjust. If that does not resolve the calendar issue, there are other settings at that can affect how times are shown on your calendar but most likely, this will fix it.
This image is a theme.plist hack