iOS Calendar: What is the meaning of Time Zone Override?

I have had issues in the past with time zones and alarms when traveling, but I think I have it solved. I have just one more point of confusion.

Current versions of iOS have the option Time Zone Override for the calendar. Mine is currently set to Off, which I think is the default. The setting can be found in Settings > Calendar > Time Zone Override

The question is: What does the setting Time Zone Override actually mean? Does it in any way affect events which have a time zone or are marked as floating.

More specifically, when I am in a different time zone, how does this setting affect the following possibilities:

  • Time Zone Override: Off, Event time zone set to home
  • Time Zone Override: On, Event time zone set to home
  • Time Zone Override: Off, Event time zone set to floating
  • Time Zone Override: On, Event time zone set to floating

Floating events

These kind of events happen always at the same time of day. An event called "Wake up" set for 6 AM and with the time zone set to Floating will always occur at 6 AM.

If you are in LA, it will occur at 6 AM, if you are in Hong Kong, it will also occur at 6 AM.

The time zone in Settings > General > Date & Time is relevant for floating events.


Regular events (Time Zone set to GMT+1 with DST)

You are in London and create an event "Process emails" for 4 PM (time zone set to London, GMT+1).

Turn on time zone override and set it to New York. Your event will now show up at 8 AM (GMT-4).


To answer your specific scenarios

  • Time Zone Override: Off, Event time zone set to home

    An event at 6 AM will be displayed at 6 AM

  • Time Zone Override: On, Event time zone set to home

    An event at 6 AM will be displayed at 1 AM (London to NY)

  • Time Zone Override: Off, Event time zone set to floating

    An event at 6 AM will always be displayed at 6 AM, no matter where you are.

  • Time Zone Override: On, Event time zone set to floating

    An event at 6 AM will always be displayed at 6 AM, no matter where you are.