I have been using the ISO 8601 standard date format long before the standard was published in 1988. I have changed the date formats to the ISO 8601 standard in Language & Region since I switched to using Apple systems. I have been tracking down a problem with a third-party application that normally displays dates in the YYYY-MM-DD format as I have configured them but will on some functions switch to using a M/D/YYYY format. I noticed that the Date & Time preference pane always uses a M/D/YYYY format when displaying the current date above the calendar and ignores the date format set under Language & Regions. The only way to change how the date is displayed above the calendar to YYYY-MM-DD is to change my location from the United States to Canada. When I do this the date problems with the third-party application disappears. Is there a way to force the use of the ISO 8601 date standard without switching my location to Canada?