Setting ISO 8601 Date and Time Format on Your Macintosh

Choose the Date & Time control panel. The following will appear:

Date & Time Control Panel
Macintosh Date & Time Control Panel

Click on both Date Formats... and Time Formats..., which will cause the two dialog boxes below to be displayed.

Set the Long Date and Short Date formats as shown in the first illustration. Note that Custom and Year-Month-Day have been selected and all four check boxes are checked.

Note also that, for the long date style, the year-month-day sequence (and its punctuation) is simply a recommendation. ISO 8601 does not deal with long dates (where the month is spelled out).

Date Format Dialog Box
Macintosh Date Format Dialog Box

Click on OK when you have finished setting the Date format.

Set 24-hour time, as shown in the next illustration.

Time Format Dialog Box
Macintosh Time Format Dialog Box

Click on OK when you have finished setting the Time format.

Close this window when you've finished with it. The SI Navigator window will still be open.

We would like to express our appreciation to Bob Baumel, who is a geophysicist and also a member of the U.S. Metric Association, for contributing the procedure and screen shots for this page.