In the United States, the state of Indiana observes Daylight Saving Time (DST) for the first time in many counties on April 2, 2006 (02-April-2006). Some counties in Indiana also change from the Eastern to Central time zone. This article explains how to adjust your Mac for these changes.
Note: If you live in an Indiana county that observed Daylight Saving Time before 2006, no changes are necessary.
Use Date & Time preferences to choose a Central time zone city, such as Chicago, on or after 02-April-2006.
Your steps depend on which version of Mac OS X you are using.
Mac OS X 10.4 or later
Download and install the Mac OS X 10.4.5 Update, or later. This contains updated Daylight Saving Time rules to automatically maintain the proper time.
Mac OS X 10.3.9 or earlier
Use Date & Time preferences to choose an Eastern time zone city, such as Detroit, on or after 02-April-2006.